U.S. patent number 9,991,914 [Application Number 15/595,538] was granted by the patent office on 2018-06-05 for bi-directional radio frequency front-end (rffe).
This patent grant is currently assigned to Amazon Technologies, Inc.. The grantee listed for this patent is Amazon Technologies, Inc.. Invention is credited to Varadarajan Gopalakrishnan, In Chul Hyun, Cheol Su Kim, Tzung-I Lee, Omar Fawazhashim Zakaria.
United States Patent |
9,991,914 |
Lee , et al. |
June 5, 2018 |
Bi-directional radio frequency front-end (RFFE)
Abstract
Technology for a bi-directional radio frequency front-end (RFFE)
architecture with high selectivity performance is described. One
RFFE has a first mixer that receives a LO signal from the LO
circuit and a transmit (TX) signal, having a first frequency, from
a transmitter and produces a down-converted TX signal for channel
bandwidth filtering, the TX signal having a second frequency that
is lower than the first frequency. A programmable filter circuit,
in response to a selection signal, filters the down-converted TX
signal according to a selected channel bandwidth. The second mixer
receives the LO signal from the LO circuit and a channel-filtered
TX signal from the programmable filter circuit and produces an
up-converted TX signal having the first frequency. The power
amplifier amplifies the up-converted TX signal to produce an output
TX signal to cause an antenna to radiate electromagnetic energy in
the selected channel bandwidth.
Inventors: |
Lee; Tzung-I (San Jose, CA),
Zakaria; Omar Fawazhashim (Santa Clara, CA), Kim; Cheol
Su (San Jose, CA), Gopalakrishnan; Varadarajan
(Cupertino, CA), Hyun; In Chul (San Jose, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Amazon Technologies, Inc. |
Seattle |
WA |
US |
|
|
Assignee: |
Amazon Technologies, Inc.
(Seattle, WA)
|
Family
ID: |
62235594 |
Appl.
No.: |
15/595,538 |
Filed: |
May 15, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
52/52 (20130101); H04B 1/0475 (20130101); H04B
1/0092 (20130101); H04W 84/18 (20130101) |
Current International
Class: |
H04B
1/04 (20060101); H04W 72/04 (20090101); H04B
1/00 (20060101); H04W 52/52 (20090101); H04W
84/18 (20090101) |
Field of
Search: |
;455/114.3 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Phu; Sanh
Attorney, Agent or Firm: Lowenstein Sandler LLP
Claims
What is claimed is:
1. A radio frequency front-end (RFFE) circuit comprising: a first
port configured to couple to a transmitter; a second port
configured to couple to an antenna; a local oscillator (LO) circuit
configured to generate a LO signal; a first mixer coupled to the LO
circuit and the first port, wherein the first mixer is configured
to produce a first intermediate frequency (IF) signal; a
programmable filter circuit coupled to the first mixer, wherein the
programmable filter circuit is configured to filter the first IF
signal based on a first channel bandwidth of a plurality of channel
bandwidths to produce a channel-filtered IF signal corresponding to
the first channel bandwidth; a second mixer coupled to the LO
circuit and the programmable filter circuit; a power amplifier
coupled to the second mixer; a third port configured to couple to a
receiver; and a low-noise amplifier (LNA) coupled to the second
port, wherein the LNA is configured to produce a filtered RX
signal, wherein: the second mixer is further coupled to the LNA;
the second mixer is configured to produce a IF signal; the IF
signal has a first frequency that is lower than a second frequency
of the filtered RX signal; the programmable filter circuit is
configured to filter the IF signal based on a second channel
bandwidth of the plurality of channel bandwidths to produce a
channel-filtered IF signal corresponding to the second channel
bandwidth; and the first mixer is further configured to receive the
LO signal and the channel-filtered IF signal to produce an input RX
signal having the second frequency.
2. The RFFE circuit of claim 1, wherein the first port is coupled
to a first port of a radio and the third port is coupled to a
second port of the radio, wherein the radio comprises the
transmitter and the receiver, wherein the RFFE circuit is a first
integrated circuit, and wherein the radio is a second integrated
circuit that is different than the first integrated circuit.
3. The RFFE circuit of claim 1, wherein the first port is coupled
to the transmitter of a first radio, wherein the RFFE further
comprises: a fourth port configured to couple to a second receiver
of a second radio; a fifth port configured to couple to a second
antenna; a second LO circuit configured to generate a second LO
signal; a third mixer coupled to the second LO circuit; a second
programmable filter circuit coupled to the third mixer; a fourth
mixer coupled to the second LO circuit and the second programmable
filter circuit; a second LNA coupled to the fifth port, wherein the
second LNA is configured to produce a second filtered RX signal,
wherein: the fourth mixer is further coupled to the second LNA; the
fourth mixer is further configured to receive the second LO signal
and the second filtered RX signal and produce a third IF signal;
the third IF signal has a third frequency that is lower than a
fourth frequency of the second filtered RX signal; the second
programmable filter circuit is configured to filter the second IF
signal based on a second channel bandwidth of the plurality of
channel bandwidths to produce a second channel-filtered IF signal
corresponding to the second channel bandwidth; and the third mixer
is further configured to receive the second LO signal and the
second channel-filtered IF signal to produce a second input RX
signal having the fourth frequency.
4. The RFFE circuit of claim 3, wherein the first radio comprises
the transmitter and the receiver and the second radio comprises the
second receiver, wherein the RFFE circuit is a first integrated
circuit, wherein the first radio is a second integrated circuit
that is different than the first integrated circuit, and wherein
the second radio is a third integrated circuit that is different
than the first integrated circuit.
5. A radio frequency front-end (RFFE) circuit comprising: a first
port configured to couple to a transmitter; a second port
configured to couple to an antenna; a local oscillator (LO) circuit
configured to generate a LO signal; a first mixer coupled to the LO
circuit and the first port, wherein the first mixer is configured
to produce a first intermediate frequency (IF) signal; a
programmable filter circuit coupled to the first mixer, wherein the
programmable filter circuit is configured to filter the first IF
signal based on a first channel bandwidth of a plurality of channel
bandwidths to produce a channel-filtered IF signal corresponding to
the first channel bandwidth; a second mixer coupled to the LO
circuit and the programmable filter circuit, wherein the second
mixer is configured to produce a filtered TX signal; a power
amplifier coupled to the second mixer, wherein the first port is
coupled to the transmitter of a first radio, wherein the RFFE
further comprises: a third port configured to couple to a second
transmitter of a second radio; a fourth port configured to couple
to a second antenna; a second LO circuit configured to generate a
second LO signal; a third mixer coupled to the second LO circuit
and the fourth port, wherein the third mixer is configured to
produce a second IF signal; a second programmable filter circuit
coupled to the third mixer, wherein the second programmable filter
circuit is configured to filter the second IF signal based on a
second channel bandwidth of the plurality of channel bandwidths to
produce a second channel-filtered IF signal corresponding to the
second channel bandwidth; a fourth mixer coupled to the second LO
circuit and the second programmable filter circuit, wherein the
fourth mixer is configured to produce a second filtered TX signal;
and a second power amplifier coupled to the fourth mixer.
6. The RFFE circuit of claim 5, wherein the first radio comprises
the transmitter and the second radio comprises the second
transmitter, wherein the RFFE circuit is a first integrated
circuit, wherein the first radio is a second integrated circuit
that is different than the first integrated circuit, and wherein
the second radio is a third integrated circuit that is different
than the first integrated circuit.
7. The RFFE circuit of claim 1, wherein the programmable filter
circuit comprises: a first multi-port switch coupled to the first
mixer; a second multi-port switch coupled to the second mixer; a
first channel band pass filter (BPF) disposed along a first channel
path between the first multi-port switch and the second multi-port
switch, wherein the first channel BPF is configured to filter the
first IF signal based on a first channel bandwidth of the plurality
of channel bandwidths to produce the channel-filtered IF signal
corresponding to the first channel bandwidth; and a second channel
BPF disposed along a second channel path between the second
multi-port switch and the second multi-port switch, wherein the
second channel BPF is configured to filter the first IF signal
based on a second channel bandwidth of the plurality of channel
bandwidths to produce the channel-filtered IF signal corresponding
to the second channel bandwidth.
8. The RFFE circuit of claim 7, wherein the programmable filter
circuit comprises a third channel BPF disposed along a third
channel path between the first multi-port switch and the second
multi-port switch, wherein the third channel BPF is configured to
filter the first IF signal based on a third channel bandwidth of
the plurality of channel bandwidths to produce the channel-filtered
IF signal corresponding to the third channel bandwidth.
9. The RFFE circuit of claim 1, further comprising: a first driver
amplifier (DA) coupled to the first port; a first BPF coupled to
the first DA and the first mixer; a second BPF coupled to the LO
circuit; a second DA coupled to the second BPF and the first mixer;
a third DA coupled to the first mixer; a third BPF coupled to the
LO circuit; a fourth DA coupled to the third BPF and the second
mixer; and a fourth BPF coupled to the second mixer and the power
amplifier.
10. The RFFE circuit of claim 9, wherein the programmable filter
circuit comprises: a first multi-port switch coupled to the third
DA; a second multi-port switch coupled to the second mixer, a first
channel band pass filter (BPF) disposed along a first channel path
between the first multi-port switch and the second multi-port
switch; a second channel BPF disposed along a second channel path
between the second multi-port switch and the second multi-port
switch; and a third channel BPF disposed along a third channel path
between the first multi-port switch and the second multi-port
switch.
11. The RFFE circuit of claim 9, further comprising: a first switch
coupled to the first port, the third port, and the first BPF,
wherein the first DA is coupled between the first port and the
first switch; a fifth DA; a second switch coupled to the first
mixer; a third switch coupled to the programmable filter circuit,
wherein the third DA is disposed along a TX path between the second
switch and the third switch, and wherein the fifth DA is disposed
along a RX path between the second switch and the third switch; a
fifth BPF coupled to the second mixer; a low-noise amplifier (LNA);
a fourth switch coupled to the fourth BPF; and a fifth switch
coupled to the second port, wherein the LNA and the fifth BPF are
disposed along a TX path between the fourth switch and the fifth
switch, and wherein the power amplifier is disposed along a RX path
between the fourth switch and the fifth switch.
12. An electronic device comprising: a zero intermediate frequency
(ZIF) transmitter; and radio frequency front-end (RFFE) circuitry
coupled to the ZIF transmitter, wherein the RFFE circuitry
comprises: a first port coupled to the transmitter; a second port
coupled to a first antenna; a local oscillator (LO) circuit
configured to generate a LO signal; a first mixer coupled to the LO
circuit and the first port, wherein the first mixer is configured
to produce a first intermediate frequency (IF) signal; a
programmable filter circuit coupled to the first mixer, wherein the
programmable filter circuit is configured to filter the first IF
signal based on a first channel bandwidth of a plurality of channel
bandwidths to produce a channel-filtered IF signal corresponding to
the first channel bandwidth; a second mixer coupled to the LO
circuit and the programmable filter circuit, wherein the second
mixer is configured to produce a filtered transmit (TX) signal; and
a power amplifier coupled to the second mixer and the second port;
a ZIF receiver; and second RFFE circuitry comprising: a third port
configured to couple to the ZIF receiver; a fourth port configured
to couple to a second antenna; a second local oscillator (LO)
circuit configured to generate a second LO signal; a low noise
amplifier (LNA) coupled to the fourth port, wherein the LNA is
configured to produce a filtered RX signal; a third mixer coupled
to the second LO circuit and the LNA; a second programmable filter
circuit coupled to the third mixer, wherein the second programmable
filter circuit is configured to filter the second IF signal based
on a second channel bandwidth of the plurality of channel
bandwidths to produce a second channel-filtered IF signal
corresponding to the second channel bandwidth; and a fourth mixer
coupled to the second LO circuit and the second programmable filter
circuit.
13. The electronic device of claim 12, further comprising a radio
comprising the ZIF receiver and the ZIF transmitter.
14. The electronic device of claim 12, further comprising a first
radio comprising the ZIF transmitter and a second radio comprising
the ZIF receiver.
15. A mesh network device comprising: a processing device; a first
antenna; a first radio coupled to the processing device, the first
radio comprising a first transmitter and a first receiver; and
first circuitry coupled between the first radio and the first
antenna and coupled to the processing device, wherein the first
circuitry comprises: a first port coupled to the first transmitter;
a second port coupled to the first antenna; a local oscillator (LO)
circuit configured to generate a LO signal; a first mixer coupled
to the LO circuit and the first port, wherein the first mixer is
configured to produce a down-converted TX signal; a programmable
filter circuit coupled to the first mixer, wherein the programmable
filter circuit, in response to a selection signal received from the
processing device, is configured to filter the down-converted TX
signal according to a selected channel bandwidth of a plurality of
channel bandwidths to produce a channel-filtered TX signal
corresponding to the selected channel bandwidth; a second mixer
coupled to the LO circuit and the programmable filter circuit,
wherein the second mixer is configured to produce an up-converted
TX signal; and a power amplifier coupled to the second mixer,
wherein the first circuitry further comprises: a third port coupled
to the first receiver; and a low-noise amplifier (LNA) coupled to
the second port, wherein the LNA is configured to produce a
filtered RX signal, wherein: the second mixer is further coupled to
the LNA; the second mixer is further configured to produce a
down-converted RX signal; the programmable filter circuit, in
response to a second selection signal, is configured to filter the
down-converted RX signal according to a second selected channel
bandwidth of the plurality of channel bandwidths to produce a
channel-filtered RX signal corresponding to the second selected
channel bandwidth; and the first mixer is further configured to
produce an up-converted RX signal.
16. The mesh network device of claim 15, further comprising: a
second antenna; a second radio coupled to the processing device,
the second radio comprising a second transmitter and a second
receiver; and second circuitry coupled between the second radio and
the second antenna and coupled to the processing device, wherein
the second circuitry comprises: a fourth port coupled to the second
transmitter; a fifth port coupled to the second antenna; a second
LO circuit configured to generate a second LO signal; a third mixer
coupled to the second LO circuit and the fourth port, wherein the
third mixer is configured to produce a second down-converted TX
signal; a second programmable filter circuit coupled to the third
mixer, wherein the second programmable filter circuit, in response
to a third selection signal received from the processing device, is
configured to filter the second down-converted TX signal according
to a third selected channel bandwidth of the plurality of channel
bandwidths to produce a second channel-filtered TX signal
corresponding to the third selected channel bandwidth; a fourth
mixer coupled to the second LO circuit and the second programmable
filter circuit, wherein the fourth mixer is configured to produce a
second up-converted TX signal; and a second power amplifier coupled
to the fourth mixer.
17. The mesh network device of claim 16, wherein the second
circuitry further comprises: a sixth port coupled to the second
receiver; and a second LNA coupled to the fifth port, wherein the
second LNA is configured to produce a second filtered RX signal,
wherein: the fourth mixer is further coupled to the second LNA; the
fourth mixer is further configured to produce a second
down-converted RX signal; the second programmable filter circuit,
in response to a fourth selection signal, is configured to filter
the second down-converted RX signal according to a fourth selected
channel bandwidth of the plurality of channel bandwidths to produce
a second channel-filtered RX signal corresponding to the fourth
selected channel bandwidth; and the third mixer is further
configured to produce a second up-converted RX signal.
Description
BACKGROUND
A large and growing population of users is enjoying entertainment
through the consumption of digital media items, such as music,
movies, images, electronic books, and so on. The users employ
various electronic devices to consume such media items. Among these
electronic devices (referred to herein as user devices or user
equipment) are electronic book readers, cellular telephones,
personal digital assistants (PDAs), portable media players, tablet
computers, netbooks, laptops and the like. These electronic devices
wirelessly communicate with a communications infrastructure to
enable the consumption of the digital media items. In order to
wirelessly communicate with other devices, these electronic devices
include one or more antennas.
BRIEF DESCRIPTION OF DRAWINGS
The present inventions will be understood more fully from the
detailed description given below and from the accompanying drawings
of various embodiments of the present invention, which, however,
should not be taken to limit the present invention to the specific
embodiments, but are for explanation and understanding only.
FIG. 1 is a network diagram of network hardware devices organized
in a wireless mesh network (WMN) for content distribution to client
devices in an environment of limited connectivity to broadband
Internet infrastructure according to one embodiment.
FIG. 2 is a block diagram of a network hardware device with five
radios operating concurrently in a WMN according to one
embodiment.
FIG. 3 is a block diagram of a mesh node with multiple radios
according to one embodiment.
FIG. 4 is a block diagram of a mesh network device according to one
embodiment.
FIG. 5 is a block diagram of a RFFE circuit with a programmable
filter circuit according to various embodiments.
FIG. 6A is a block diagram of a transmit (TX) path within RFFE
circuitry with high selectivity performance in multi-channel
operation according to one embodiment.
FIG. 6B is a block diagram of a receive (RX) path within the RFFE
circuitry of FIG. 6A according to one embodiment.
FIG. 7 is a block diagram of RFFE circuitry with high selectivity
performance in multi-channel operation with multiple radios and
multiple antennas according to one embodiment.
FIG. 8 is a graph showing a transmit out-of-channel noise (TXOON)
with RFFE circuitry of FIG. 7 according to one embodiment.
FIG. 9 is a block diagram of two radios that operate in two
channels at the same time within a single band two radios in a
single band which communicate with two channels at the same time
according to one embodiment.
FIG. 10 is a graph showing a baseband spectrum of a zero
intermediate frequency (ZIF) transceiver with and without the RFFE
circuitry according to one embodiment.
FIG. 11 is a graph 1100 showing packet error rate (PER) as a
function of the adjacent channel interference (ACI) power of the
ZIF transceiver with and without the RFFE circuitry according to
one embodiment.
FIG. 12 is a block diagram of two radios that operate in two
channels at the same time within a single band according to another
embodiment.
FIG. 13 illustrates a multi-radio, multi-channel (MRMC) network
device according to one embodiment.
FIG. 14 is a block diagram of a network hardware device according
to one embodiment.
DETAILED DESCRIPTION
Technology for a bi-directional radio frequency front-end (RFFE)
architecture with high selectivity performance is described. One
RFFE has a first mixer that receives a LO signal from the LO
circuit and a transmit (TX) signal, having a first frequency, from
a first port of a transmitter and produces a down-converted TX
signal for channel bandwidth filtering, the TX signal having a
second frequency that is lower than the first frequency. Mixers can
be used to shift signals from one frequency range to another. A
mixer can down-covert a signal from the first frequency to a second
frequency that is lower than the first frequency. Similarly, the
mixer can up-convert a signal from the second frequency to the
first frequency that is higher than the second frequency. A
programmable filter circuit, in response to a selection signal,
filters the down-converted TX signal according to a selected
channel bandwidth. The second mixer receives the LO signal from the
LO circuit and a channel-filtered TX signal from the programmable
filter and produces an up-converted TX signal having the first
frequency. The power amplifier amplifies the up-converted TX signal
to produce an output TX signal on a second port to cause an antenna
to radiate electromagnetic energy in the selected channel
bandwidth.
Also, described herein is a wireless mesh network (WMN) containing
multiple mesh network devices, organized in a mesh topology, in
which the RFFE architecture may be deployed. The mesh network
devices in the WMN cooperate in distribution of content files to
client consumption devices in an environment of limited
connectivity to broadband Internet infrastructure. The embodiments
described herein may be implemented where there is the lack, or
slow rollout, of suitable broadband Internet infrastructure in
developing nations, for example. These mesh networks can be used in
the interim before broadband Internet infrastructure becomes widely
available in those developing nations. The network hardware devices
are also referred to herein as mesh routers, mesh network devices,
mesh nodes, Meshboxes, or Meshbox nodes. Multiple network hardware
devices wirelessly are connected through a network backbone formed
by multiple peer-to-peer (P2P) wireless connections (i.e., wireless
connections between multiple pairs of the network hardware
devices). The multiple network devices are wirelessly connected to
one or more client consumption devices by node-to-client (N2C)
wireless connections. The multiple network devices are wirelessly
connected to a mesh network control service (MNCS) device by
cellular connections. The content file (or generally a content item
or object) may be any type of format of digital content, including,
for example, electronic texts (e.g., eBooks, electronic magazines,
digital newspapers, etc.), digital audio (e.g., music, audible
books, etc.), digital video (e.g., movies, television, short clips,
etc.), images (e.g., art, photographs, etc.), or multi-media
content. The client consumption devices may include any type of
content rendering devices such as electronic book readers, portable
digital assistants, mobile phones, laptop computers, portable media
players, tablet computers, cameras, video cameras, netbooks,
notebooks, desktop computers, gaming consoles, DVD players, media
centers, and the like.
The embodiments of the mesh network devices may be used to deliver
content, such as video, music, literature, or the like, to users
who do not have access to broadband Internet connections because
the mesh network devices may be deployed in an environment of
limited connectivity to broadband Internet infrastructure. In some
of the embodiments described herein, the mesh network architecture
does not include "gateway" nodes that are capable of forwarding
broadband mesh traffic to the Internet. The mesh network
architecture may include a limited number of point-of-presence
(POP) nodes that do have access to the Internet, but the majority
of mesh network devices is capable of forwarding broadband mesh
traffic between the mesh network devices for delivering content to
client consumption devices that would otherwise not have broadband
connections to the Internet. Alternatively, instead of POP node
having access to broadband Internet infrastructure, the POP node is
coupled to storage devices that store the available content for the
WMN. The WMN may be self-contained in the sense that content lives
in, travels through, and is consumed by nodes in the mesh network.
In some embodiments, the mesh network architecture includes a large
number of mesh nodes, called Meshbox nodes. From a hardware
perspective, the Meshbox node functions much like an
enterprise-class router with the added capability of supporting P2P
connections to form a network backbone of the WMN. From a software
perspective, the Meshbox nodes provide much of the capability of a
standard content distribution network (CDN), but in a localized
manner. The WMN can be deployed in a geographical area in which
broadband Internet is limited. The WMN can scale to support a
geographic area based on the number of mesh network devices, and
the corresponding distances for successful communications over WLAN
channels by those mesh network devices.
Although various embodiments herein are directed to content
delivery, such as for the Amazon Instant Video (AIV) service, the
WMNs, and corresponding mesh network devices, can be used as a
platform suitable for delivering high bandwidth content in any
application where low latency is not critical or access patterns
are predictable. The embodiments described herein are compatible
with existing content delivery technologies, and may leverage
architectural solutions, such as CDN surfaces like the Amazon AWS
CloudFront service. Amazon CloudFront CDN is a global CDN service
that integrates with other Amazon Web services products to
distribute content to end users with low latency and high data
transfer speeds. The embodiments described herein can be an
extension to this global CDN, but in environments where there is
limited broadband Internet infrastructure. The embodiments
described herein may provide users in these environments with a
content delivery experience equivalent to what the users would
receive on a traditional broadband Internet connection. The
embodiments described herein may be used to optimize deployment for
traffic types (e.g. streaming video) that are increasingly becoming
a significant percentage of broadband traffic and taxing existing
infrastructure in a way that is not sustainable.
FIGS. 1-4 are generally directed to network hardware devices,
organized in a wireless mesh network, for content distribution to
client consumption devices in environments of limited connectivity
to broadband internet infrastructure. The embodiments described
herein may be deployed in these network hardware devices. FIGS.
5-12 are generally directed to embodiments of the RFFE architecture
with high selectivity performance. FIGS. 13-14-15 are generally
directed to multi-radio, multi-channel (MRMC) mesh network devices
that may implement various embodiments described herein.
FIG. 1 is a network diagram of network hardware devices 102-110,
organized in a wireless mesh network (WMN) 100, for content
distribution to client devices in an environment of limited
connectivity to broadband Internet infrastructure according to one
embodiment. The WMN 100 includes multiple network hardware devices
102-110 that connect together to transfer digital content through
the WMN 100 to be delivered to one or more client consumption
devices connected to the WMN 100. In the depicted embodiment, the
WMN 100 includes a miniature point-of-presence (mini-POP) device
102 (also referred to as mini-POP device), having at least one of a
first wired connection to an attached storage device 103 or a
point-to-point wireless connection 105 to a CDN device 107 (server
of a CDN or a CDN node) of an Internet Service Provider (ISP). The
CDN device 107 may be a POP device (also referred to as a POP
device), an edge server, a content server device or another device
of the CDN. The mini-POP device 102 may be similar to POP devices
of a CDN in operation. However, the mini-POP device 102 is called a
miniature to differentiate it from a POP device of a CDN given the
nature of the mini-POP device 102 being a single ingress point to
the WMN 100; whereas, the POP device of a CDN may be one of many in
the CDN.
The point-to-point wireless connection 105 may be established over
a point-to-point wireless link 115 between the mini-POP device 102
and the CDN device 107. Alternatively, the point-to-point wireless
connection 105 may be established over a directional microwave link
between the mini-POP device 102 and the CDN device 107. In other
embodiments, the mini-POP device 102 is a single ingress node of
the WMN 100 for the content files stored in the WMN 100. Meaning
the mini-POP 102 may be the only node in the WMN 100 having access
to the attached storage or a communication channel to retrieve
content files stored outside of the WMN 100. In other embodiments,
multiple mini-POP devices may be deployed in the WMN 100, but the
number of mini-POP devices should be much smaller than a total
number of network hardware devices in the WMN 100. Although a
point-to-point wireless connection can be used, in other
embodiments, other communication channels may be used. For example,
a microwave communication channel may be used to exchange data.
Other long distance communication channels may be used, such as a
fiber-optic link, satellite link, cellular link, or the like. The
network hardware devices of the WMN 100 may not have direct access
to the mini-POP device 102, but can use one or more intervening
nodes to get content from the mini-POP device. The intervening
nodes may also cache content that can be accessed by other nodes.
The network hardware devices may also determine a shortest possible
route between the requesting node and a node where a particular
content file is stored.
The CDN device 107 may be located at a datacenter 119 and may be
connected to the Internet 117. The CDN device 107 may be one of
many devices in the global CDN and may implement the Amazon
CloudFront technology. The CDN device 107 and the datacenter 119
may be co-located with the equipment of the point-to-point wireless
link 155. The point-to-point wireless connection 105 can be
considered a broadband connection for the WMN 100. In some cases,
the mini-POP device 102 does not have an Internet connection via
the point-to-point wireless connection 105 and the content is
stored only in the attached storage device 103 for a self-contained
WMN 100.
The WMN 100 also includes multiple mesh nodes 104-110 (also
referred to herein as meshbox nodes and network hardware devices).
The mesh nodes 104-110 may establish multiple P2P wireless
connections 109 between mesh nodes 104-110 to form a network
backbone. It should be noted that only some of the possible P2P
wireless connections 109 are shown between the mesh nodes 104-110
in FIG. 1. In particular, a first mesh node 104 is wirelessly
coupled to the mini-POP device 102 via a first P2P wireless
connection 109, as well as being wirelessly coupled to a second
mesh node 106 via a second P2P wireless connection 109 and a third
mesh node 108 via a third P2P wireless connection. The mesh nodes
104-110 (and the mini-POP device 102) are MRMC mesh network
devices. As described herein, the mesh nodes 104-110 do not
necessarily have reliable access to the CDN device 107. The mesh
nodes 104-110 (and the mini-POP device 102) wirelessly communicate
with other nodes via the network backbone via a first set of WLAN
channels reserved for inter-node communications. The mesh nodes
102-110 communicate data with one another via the first set of WLAN
channels at a first frequency of approximately 5 GHz (e.g., 5 GHz
band of the Wi-Fi.RTM. network technologies).
Each of the mesh nodes 104-110 (and the mini-POP device 102) also
includes multiple node-to-client (N2C) wireless connections 111 to
wirelessly communicate with one or more client consumption devices
via a second set of WLAN channels reserved for serving content
files to client consumption devices connected to the WMN 100. In
particular, the second mesh node 106 is wirelessly coupled to a
first client consumption device 112 (AIV client) via a first N2C
wireless connection 111, a second client consumption device 114
(AIV client) via a second N2C wireless connection 111, and a third
client consumption device 116 (e.g., the Fire TV device) via a
third N2C wireless connection 111. The second node 106 wirelessly
communicates with the client consumption devices via the second set
of WLAN channels at a second frequency of approximately 2.4 GHz
(e.g., 2.4 GHz band of the Wi-Fi.RTM. network technologies).
Each of the mesh nodes 104-110 (and the mini-POP device 102) also
includes a cellular connection 113 to wirelessly communicate
control data between the respective node and a second device 118
hosting a mesh network control service described below. The
cellular connection 113 may be a low bandwidth, high availability
connection to the Internet 117 provided by a cellular network. The
cellular connection 113 may have a lower bandwidth than the
point-to-point wireless connection 105. There may be many uses for
this connection including, health monitoring of the mesh nodes,
collecting network statistics of the mesh nodes, configuring the
mesh nodes, and providing client access to other services. In
particular, the mesh node 110 connects to a cellular network 121
via the cellular connection 113. The cellular network 121 is
coupled to the second device 118 via the Internet 117. The second
device 118 may be one of a collection of devices organized as a
cloud computing system that that hosts one or more services 120.
The services 120 may include cloud services to control setup of the
mesh nodes, the content delivery service (e.g., AIV origin), as
well as other cloud services. The mesh network control service can
be one or more cloud services. The cloud services can include a
metric collector service, a health and status service, a link
selection service, a channel selection service, a content request
aggregation service, or the like. There may be APIs for each of
these services. Although this cellular connection may provide
access to the Internet 117, the amount of traffic that goes through
this connection should be minimized, since it may be a relatively
costly link. This cellular connection 113 may be used to
communicate various control data to configure the mesh network for
content delivery. In addition, the cellular connection 113 can
provide a global view of the state of the WMN 100 remotely. Also,
the cellular connection 113 may aid in the debugging and
optimization of the WMN 100. In other embodiments, other low
bandwidth services may also be offered through this link (e.g.
email, shopping on Amazon.com, or the like).
Although only four mesh nodes 104-110 are illustrated in FIG. 1,
the WMN 100 can use many mesh nodes, wireless connected together in
a mesh network, to move content through the WMN 100. The 5 GHz WLAN
channels are reserved for inter-node communications (i.e., the
network backbone). Theoretically, there is no limit to the number
of links a given Meshbox node can have to its neighbor nodes.
However, practical considerations, including memory, routing
complexity, physical radio resources, and link bandwidth
requirements, may place a limit on the number of links maintained
to neighboring mesh nodes. Meshbox nodes may function as
traditional access points (APs) for devices running AIV client
software. The 2.4 GHz WLAN channels are reserved for serving client
consumption devices. The 2.4 GHz band may be chosen for serving
clients because there is a wider device adoption and support for
this band. Additionally, the bandwidth requirements for serving
client consumption devices will be lower than that of the network
backbone. The number of clients that each Meshbox node can support
depends on a number of factors including memory, bandwidth
requirements of the client, incoming bandwidth that the Meshbox
node can support, and the like. For example, the Meshbox nodes
provide coverage to users who subscribe to the content delivery
service and consume that service through an AIV client on the
client consumption devices (e.g., a mobile phone, a set top box, a
tablet, or the like). It should be noted that there is a 1-to-many
relationship between Meshbox nodes and households (not just between
nodes and clients). This means the service can be provided without
necessarily requiring a customer to have a Meshbox node located in
their house, as illustrated in FIG. 1. As illustrated, the second
mesh node 106 services two client consumption devices 112, 114
(e.g., AIV clients) located in a first house, as well as a third
client consumption device 116 (e.g., the Fire TV client) located in
a second house. The Meshbox nodes can be located in various
structures, and there can be multiple Meshbox nodes in a single
structure.
The WMN 100 may be used to address two main challenges: moving high
bandwidth content to users and storing that content in the network
itself. The first challenge may be addressed in hardware through
the radio links between mesh nodes and the radio links between mesh
nodes and client consumption devices, and in software by the
routing protocols used to decide where to push traffic and link and
channel management used to configure the WMN 100. The second
challenge may be addressed by borrowing from the existing content
distribution strategy employed by the content delivery services
(e.g., AIV) using caches of content close to the user. The
architecture to support content caching is known as a CDN. An
example CDN implementation is the AWS CloudFront service. The AWS
CloudFront service may include several point-of-presence (POP)
racks that are co-located in datacenters that see a lot of customer
traffic (for example an ISP), such as illustrated in datacenter 119
in FIG. 1. A POP rack has server devices to handle incoming client
requests and storage devices to cache content for these requests.
If the content is present in the POP rack, the content is served to
the client consumption device from there. If it is not stored in
the POP rack, a cache miss is triggered and the content is fetched
from the next level of cache, culminating in the "origin," which is
a central repository for all available content. In contrast, as
illustrated in FIG. 1, the WMN 100 includes the mini-POP device 102
that is designed to handle smaller amounts of traffic than a
typical POP rack. Architecturally, the mini-POP device 102 may be
designed as a Meshbox node with storage attached (e.g. external
hard disk). The mini-POP device 102 may function identically to a
POP device with the exception of how cache misses are handled.
Because of the lack of broadband Internet infrastructure, the
mini-POP device 102 has no traditional Internet connection to the
next level of cache. The following describes two different
solutions for providing the next level of cache to the mini-POP
device 102.
In one embodiment, the mini-POP device 102 is coupled to an
existing CDN device 107 via a directional microwave link or other
point-to-point wireless link 115. A directional microwave link is a
fairly easy way to get a relatively high bandwidth connection
between two points. However, line of sight is required which might
not be possible with terrain or building constraints. In another
embodiment, the mini-POP device 102 can operate with a human in the
loop (HITL) to update the cache contents. HITL implies that a
person will be tasked with manually swapping out the hard drives
with a hard drives with the updated content or adding the content
to the hard drive. This solution may be a relatively high bandwidth
but extremely high latency solution and may only be suitable if the
use cases allow longer times (e.g., hours) to service a cache
miss.
The WMN 100 may be considered a multi-radio multi-channel (MRMC)
mesh network. MRMC mesh networks are an evolution of traditional
single radio WMNs and a leading contender for combatting the radio
resource contention that has plagued single radio WMNs and prevents
them from scaling to any significant size. The WMN 100 has multiple
devices, each with multi-radio multi-channel (MRMC) radios. The
multiple radios for P2P connections and N2C connections of the mesh
network devices allow the WMN 100 to be scaled to a significant
size, such as 10,000 mesh nodes. For example, unlike the
conventional solutions that could not effectively scale, the
embodiments described herein can be very large scale, such as a
100.times.100 grid of nodes with 12-15 hops between nodes to serve
content to client consumption devices. The paths to fetch content
files may not be a linear path within the mesh network.
The WMN 100 can provide adequate bandwidth, especially node-to-node
bandwidth. For video, content delivery services recommend a minimum
of 900 Kbps for standard definition content and 3.5 Mbps for high
definition content. The WMN 100 can provide higher bandwidths than
those recommended for standard definition and high definition
content. Prior solutions found that for a 10,000-node mesh network
covering one square kilometer, the upper bound on inter-node
traffic is 221 kbps. The following can impact bandwidth: forwarding
traffic, wireless contention (MAC/PHY), and routing protocols.
In some embodiments, the WMN 100 can be self-contained as described
herein. The WMN 100 may be self-contained in the sense that content
resides in, travels through, and is consumed by nodes in the mesh
network without requiring the content to be fetched outside of the
WMN 100. In other embodiments, the WMN 100 can have mechanisms for
content injection and distribution. One or more of the services 120
can manage the setup of content injection and distribution. These
services (e.g., labeled mesh network control service) can be hosted
by as cloud services, such as on one or more content delivery
service devices. These mechanisms can be used for injecting content
into the network as new content is created or as user viewing
preferences change. Although these injection mechanisms may not
inject the content in real time, the content can be injected into
the WMN 100 via the point-to-point wireless connection 105 or the
HITL process at the mini-POP device 102. Availability and impact on
cost in terms of storage may be relevant factors in determining
which content is to be injected into the WMN 100 and which content
is to remain in the WMN 100. A challenge for traditional mesh
network architectures is that this content is high bandwidth (in
the case of video) and so the gateway nodes that connect the mesh
to the larger Internet must be also be high bandwidth. However,
taking a closer look at the use case reveals that this content,
although high bandwidth, does not need to be low latency. The
embodiments of the WMN 100 described herein can provide
distribution of content that is high bandwidth, but in a manner
that does not need low latency.
In some embodiments, prior to consumption by a node having an AIV
client itself or being wirelessly connected to an AIV client
executing on a client consumption device, the content may be pulled
close to that node. This may involve either predicting when content
will be consumed to proactively move it closer (referred to as
caching) or always having it close (referred to as replication).
Content replication is conceptually straightforward, but may impact
storage requirements and requires apriori knowledge on the
popularity of given titles.
Another consideration is where and how to store content in the WMN
100. The WMN 100 can provide some fault tolerance so that a single
mesh node becoming unavailable for failure or reboot has minimal
impact on availability of content to other users. This means that a
single mesh node is not the sole provider of a piece of content.
The WMN 100 can use reliability and availability mechanisms and
techniques to determine where and how to store content in the WMN
100.
The WMN 100 can be deployed in an unpredictable environment. Radio
conditions may not be constant and sudden losses of power may
occur. The WMN 100 is designed to be robust to temporary failures
of individual nodes. The WMN 100 can be designed to identify those
failures and adapt to these failures once identified. Additionally,
the WMN 100 can include mechanisms to provide secure storage of the
content that resides within the WMN 100 and prevent unauthorized
access to that content.
The cloud services 120 of the WMN 100 can include mechanisms to
deal with mesh nodes that become unavailable, adding, removing, or
modifying existing mesh nodes in the WMN 100. The cloud services
120 may also include mechanisms for remote health and management.
For example, there may be a remote health interface, a management
interface, or both to access the mesh nodes for this purpose. The
cloud services 120 can also include mechanisms for securing the WMN
100 and the content that resides in the WMN 100. For example, the
cloud services 120 can control device access, DRM, and node
authentication.
FIG. 2 is a block diagram of a network hardware device 202 with
five radios operating concurrently in a wireless mesh network 200
according to one embodiment. The wireless mesh network 200 includes
multiple network hardware devices 202-210. The network hardware
device 202 may be considered a mesh router that includes four 5 GHz
radios for the network backbone for multiple connections with other
mesh routers, i.e., network hardware devices 204-210. For example,
the network hardware device 204 may be located to the north of the
network hardware device 202 and connected over a first 5 GHz
connection. The network hardware device 206 may be located to the
east of the network hardware device 202 and connected over a second
5 GHz connection. The network hardware device 208 may be located to
the south of the network hardware device 202 and connected over a
third 5 GHz connection. The network hardware device 210 may be
located to the west of the network hardware device 202 and
connected over a fourth 5 GHz connection. In other embodiments,
additional network hardware devices can be connected to other 5 GHz
connections of the network hardware device 202. It should also be
noted that the network hardware devices 204-210 may also connect to
other network hardware devices using its respective radios. It
should also be noted that the locations of the network hardware
devices 20-210 can be in other locations that north, south, east,
and west. For example, the network hardware devices can be located
above or below the mesh network device 202, such as on another
floor of a building or house.
The network hardware device 202 also includes at least one 2.4 GHz
connection to serve client consumption devices, such as the client
consumption device 212 connected to the network hardware device
202. The network hardware device 202 may operate as a mesh router
that has five radios operating concurrently or simultaneously to
transfer mesh network traffic, as well as service connected client
consumption devices. This may require that the 5GLL and 5GLH to be
operating simultaneously and the 5GHL and 5GHH to be operating
simultaneously, as described in more detail below. It should be
noted that although the depicted embodiment illustrates and
describes five mesh nodes, in other embodiments, more than five
mesh nodes may be used in the WMN. It should be noted that FIG. 2
is a simplification of neighboring mesh network devices for a given
mesh network device. The deployment of forty or more mesh network
device may actually be located at various directions than simply
north, south, east, and west as illustrated in FIG. 2. Also, it
should be noted that here are a limited number of communication
channels available to communicate with neighboring mesh nodes in
the particular wireless technology, such as the Wi-Fi.RTM. 5 GHz
band. The embodiments of the mesh network devices, such as the
directional antennas, can help with isolation between neighboring
antennas that cannot be separated physically given the limited size
the mesh network device.
FIG. 3 is a block diagram of a mesh node 300 with multiple radios
according to one embodiment. The mesh node 300 includes a first 5
GHz radio 302, a second 5 GHz radio 304, a third 5 GHz radio 306, a
fourth 5 GHz radio 308, a 2.4 GHz radio 310, and a cellular radio
312. The first 5 GHz radio 302 creates a first P2P wireless
connection 303 between the mesh node 300 and another mesh node (not
illustrated) in a WMN. The second 5 GHz radio 304 creates a second
P2P wireless connection 305 between the mesh node 300 and another
mesh node (not illustrated) in the WMN. The third 5 GHz radio 306
creates a third P2P wireless connection 307 between the mesh node
300 and another mesh node (not illustrated) in the WMN. The fourth
5 GHz radio 308 creates a fourth P2P wireless connection 309
between the mesh node 300 and another mesh node (not illustrated)
in the WMN. The 2.4 GHz radio 310 creates a N2C wireless connection
311 between the mesh node 300 and a client consumption device (not
illustrated) in the WMN. The cellular radio 312 creates a cellular
connection between the mesh node 300 and a device in a cellular
network (not illustrated). In other embodiments, more than one 2.4
GHz radios may be used for more N2C wireless connections.
Alternatively, different number of 5 GHz radios may be used for
more or less P2P wireless connections with other mesh nodes. In
other embodiments, multiple cellular radios may be used to create
multiple cellular connections.
In another embodiment, a system of devices can be organized in a
WMN. The system may include a single ingress node for ingress of
content files into the wireless mesh network. In one embodiment,
the single ingress node is a mini-POP node that has attached
storage device(s). The single ingress node may optionally include a
point-to-point wireless connection, such as a microwave
communication channel to a node of the CDN. The single ingress node
may include a point-to-point wireless link to the Internet (e.g., a
server device of the CDN) to access content files over the
Internet. Alternatively to, or in addition to the point-to-point
wireless link, the single ingress node may include a wired
connection to a storage device to access the content files stored
on the storage device. Multiple network hardware devices are
wirelessly connected through a network backbone formed by multiple
P2P wireless connections. These P2P wireless connections are
wireless connections between different pairs of the network
hardware devices. The P2P wireless connections may be a first set
of WLAN connections that operate at a first frequency of
approximately 5.0 GHz. The multiple network hardware devices may be
wirelessly connected to one or more client consumption devices by
one or more N2C wireless connections. Also, the multiple network
hardware devices may be wirelessly connected to a mesh network
control services (MNCS) device by cellular connections. Each
network hardware device includes a cellular connection to a MNCS
service hosted by a cloud computing system. The cellular
connections may have lower bandwidths than the point-to-point
wireless link.
The system includes a first network hardware device wirelessly
connected to a first client consumption device by a first
node-to-client (N2C) wireless connection and a second network
hardware device wirelessly connected to the single ingress node.
The first network hardware device can wirelessly connect to a first
client consumption device over a first N2C connection. The N2C
wireless connection may be one of a second set of one or more WLAN
connections that operate at a second frequency of approximately 2.4
GHz. During operation, the first network hardware device may
receive a first request for a first content file from the first
client consumption device over the first N2C connection. The first
network device sends a second request for the first content file to
the second network hardware device through the network backbone via
a first set of zero or more intervening network hardware devices
between the first network hardware device and the second network
hardware device. The first network device receives the first
content file from the first network hardware device through the
network backbone via the first set of zero or more intervening
network hardware devices and sends the first content file to the
first client consumption device over the first N2C connection. In a
further embodiment, the first network hardware device includes
another radio to wirelessly connect to a MNCS device by a cellular
connection to exchange control data.
In a further embodiment, the first network hardware device is
further to receive a third request for a second content file from a
second client consumption device connected to the first network
hardware device over a second N2C connection between the first
network hardware device and the second client consumption device.
The first network hardware device sends a fourth request for the
second content file stored at a third network hardware device
through the network backbone via a second set of zero or more
intervening network hardware devices between the first network
hardware device and the third network hardware device. The first
network hardware device receives the second content file from the
third network hardware device through the network backbone via the
second set of zero or more intervening network hardware devices.
The first network hardware device sends the second content file to
the second client consumption device over the second N2C
connection.
In one embodiment, the zero or more intervening network hardware
devices of the first set are not the same as the zero or more
intervening network hardware devices of the second set. In some
embodiments, a path between the first network hardware device and
the second network hardware device could include zero or more hops
of intervening network hardware devices. In some cases, the path
may include up to 12-15 hops within a mesh network of 100.times.100
network hardware devices deployed in the WMN. In some embodiments,
a number of network hardware devices in the WMN is greater than
fifty. The WMN may include hundreds, thousands, and even tens of
thousands of network hardware devices.
In a further embodiment, the first network hardware device receive
the fourth request for the second content file from a fourth
network hardware device through the network backbone via a third
set of zero or more intervening network hardware devices between
the first network hardware device and the fourth network hardware
device. The first network hardware device sends the second content
file to the fourth network hardware device through the network
backbone via the third set of zero or more intervening network
hardware devices.
In some embodiments, the first network hardware device determines
whether the first content file is stored in memory of the first
network hardware device. The memory of the first network hardware
device may be volatile memory, non-volatile memory, or a
combination of both. When the first content file is not stored in
the memory or the storage of the first network hardware device, the
first network hardware device generates and sends the second
request to a first network hardware device of the first set.
Intervening network hardware devices can make similar
determinations to locate the first content file in the WMN. In the
event that the first content file is not stored in the second
network hardware device or any intervening nodes, the second
network hardware device can request the first content file from the
mini-POP node, as described herein. When the mini-POP node does not
store the first content file, the mini-POP can take action to
obtain the first content file, such as requesting the first content
file from a CDN over a point-to-point link. Alternatively, the
human in the loop process can be initiated as described herein.
In a further embodiment, the second network hardware device
receives the second request for the first content file and
retrieves the first content file from the single ingress node when
the first content file is not previously stored at the second
network hardware device. The second network hardware device sends a
response to the second request with the first content file
retrieved from the single ingress node. The second network hardware
device may store a copy of the first content file in memory or
persistent storage of the second network hardware device for a time
period.
In another embodiment, the single ingress node receives a request
for a content file from one of the multiple network hardware
devices over a P2P wireless connection. The request originates from
a requesting consumption device. It should be noted that a video
client can be installed on the client consumption device, on the
network hardware device, or both. The single ingress node
determines whether the content file is stored in a storage device
coupled to the single ingress node. The single ingress node
generates and sends a first notification to the requesting one of
the network hardware devices over the P2P wireless connection when
the content file is not stored in the storage device. The first
notification includes information to indicate an estimated delay
for the content file to be available for delivery. The single
ingress node generates and sends a second notification to an
operator of the first network hardware device. The second
notification includes information to indicate that the content file
has been requested by the requesting client consumption device. In
this embodiment, the notifications can be pushed to the appropriate
recipients. In another embodiment, an operator can request which
content files had been requested in the WMN and not serviced. This
can initiate the ingress of the content file into the WMN, even if
with a longer delay.
In some embodiments, the mini-POP node is coupled to a storage
device to store the content files as original content files for the
wireless mesh network. A point-to-point wireless link may be
established between the mini-POP node and a node of a CDN. In
another embodiment, the mini-POP node is coupled to a node of a
content delivery network (CDN) via a microwave communication
channel.
In a further embodiment, the second network hardware device can
wirelessly connect to a third network hardware device over a second
P2P connection. During operation, the third network hardware device
may receive a third request for a second content file from a second
client consumption device over a second N2C connection between the
third network hardware device and the second client consumption
device. The third network hardware device sends a fourth request
for the second content file to the second network hardware device
over the second P2P connection. The third network hardware device
receives the second content file from the second network hardware
device over the second P2P connection and sends the second content
file to the second client consumption device over the second N2C
connection.
In another embodiment, the first network hardware device receives
the fourth request for the second content file from the third
network hardware device. The second network hardware device
determines whether the second content file is stored in memory of
the second network hardware device. The second network hardware
device sends a fifth request to the first network hardware device
over the first P2P connection and receive the second content file
over the first P2P connection from the first network hardware
device when the second content file is not stored in the memory of
the second network hardware device. The second network hardware
device sends the second content file to the third network hardware
device over the second P2P connection.
In another embodiment, the second network hardware device may
wirelessly connect to a third network hardware device over a second
P2P connection. During operation, the third network hardware device
may receive a third request for the first content file from a
second client consumption device over a second N2C connection
between the third network hardware device and the second client
consumption device. The third network hardware device sends a
fourth request for the first content file to the second network
hardware device over the second P2P connection. The third network
hardware device receives the first content file from the first
network hardware device over the second P2P connection and sends
the first content file to the second client consumption device over
the second N2C connection.
In another embodiment, the first network hardware device receives a
request for a content file from one of the network hardware devices
over one of the P2P wireless connections. The request is from a
requesting client consumption device connected to one of the
multiple network hardware devices. The first network hardware
device determines whether the content file is stored in the storage
device. The first network hardware device generates and sends a
first notification to the one of the network hardware devices over
the one of the P2P wireless connections when the content file is
not stored in the storage device. The first notification may
include information to indicate an estimated delay for the content
file to be available for delivery. The first network hardware
device generates and sends a second notification to an operator of
the first network hardware device. The second notification may
include information to indicate that the content file has been
requested by the requesting client consumption device.
In a further embodiment, the P2P wireless connections are WLAN
connections that operate in a first frequency range and the N2C
connections are WLAN connections that operate in a second frequency
range. In another embodiment, the P2P wireless connections operate
at a first frequency of approximately 5.0 GHz and the N2C
connections operate at a second frequency of approximately 2.4
GHz.
In some embodiments, at least one of the network hardware devices
is a mini-POP) node and a point-to-point wireless link is
established between the mini-POP node and a POP node of an ISP. In
one embodiment, the point-to-point wireless link is a microwave
link (e.g., directional microwave link) between the mini-POP node
and the node of the CDN. In another embodiment, the mini-POP node
stores an index of the content files store in attached storage
devices.
In some embodiments, a mesh network architecture includes multiple
mesh nodes organized in a self-contained mesh network. The
self-contained mesh network may be self-contained in the sense that
content resides in, travels through, and is consumed by nodes in
the mesh network without requiring the content to be fetched
outside of the mesh network. Each of the mesh nodes includes a
first radio for inter-node communications with the other nodes on
multiple P2P channels, a second radio for communications with
client consumption devices on N2C channels. The mesh network
architecture also includes a mini-POP node including a radio for
inter-connection communications with at least one of the mesh nodes
on a P2P channel. The mesh network architecture also includes a
storage device coupled to the mini-POP, the storage device to store
content files for distribution to a requesting client consumption
device. The mini-POP node may be a single ingress point for content
files for the self-contained mesh network. The storage devices of
the mini-POP node may be internal drives, external drives, or both.
During operation, a first node of the mesh nodes includes a first
radio to wirelessly connect to a requesting client consumption
device via a first N2C channel to receive a first request for a
content file directly from the requesting client consumption device
via a first N2C channel between the first node and the requesting
client consumption device 1. A second radio of the first node sends
a second request for the content file to a second node via a first
set of zero or more intervening nodes between the first node and
the second node to locate the content file within the
self-contained mesh network. The second radio receives the content
file from the second node in response to the request. The first
radio sends the content file to the requesting client consumption
device via the first N2C channel. The first node determines a
location of the content file within the self-contained mesh network
and sends a second request for the content file via a second P2P
channel to at least one of the mini-POP or a second node, the
second request to initiate delivery of the content file to the
requesting client consumption device over a second path between the
location of the content file and the requesting client consumption
device.
In another embodiment, the first node stores a copy of the content
file in a storage device at the first node. The first node receives
a third request for the content file directly from a second client
consumption device via a second N2C channel between the first node
and the second client consumption device. The first node sends the
copy of the content file to the second client consumption device
via the second N2C channel in response to the third request.
In a further embodiment, the first node receives the content file
via the second P2P channel in response to the second request and
sends the content file to the requesting client consumption device
via the first N2C channel or the first P2P channel in response to
the first request. In some embodiments, the second path and the
first path are the same.
In a further embodiment, the first node includes a third radio to
communicate control data over a cellular connection between the
first node and a mesh network control service (MNCS) device.
In one embodiment, the second radio can operate with 2.times.2 MIMO
with maximum 40 MHz aggregation. This may result in per radio
throughput of not more than 300 Mbps in 5 GHz and 150 Mbps in 2.4
GHz. Even with 5 radios (4.times.5 GHz and 1.times.2.4), the peak
physical layer throughput will not need to be more than 1.4 Gbps.
For example, a scaling factor of 1.4 may be used to arrive at a CPU
frequency requirement. This implies the total processing clock
speed in the CPU should not be less than 1.96 GHz
(1.4.times.1.4=1.96 GHz). For example, the Indian ISM band has a
requirement of 23 dBm EIRP. Since the WMN 100 needs to function
under conditions where the mesh routers communicate with each other
between homes, the propagation loss through multiple walls and over
distances between homes, the link budget does not support
sensitivity requirements for 802.11ac data rates. The per-node
throughput may be limited to 300 Mbps per link--peak PHY rate. It
should be noted that the scaling factor of 1.4 is just an example.
In other cases, the scaling factor can be determined by a lot of
factors, such as CPU architecture, number of cores, Wi-Fi.RTM.
target offloading mode, NPU offload engine, software forwarding
layers (L2 vs L3), or the like.
In another embodiment, a system includes a POP node having access
to content files via at least one of data storage coupled to the
POP node or a first point-to-point connection to a first device of
an ISP. The system also includes multiple mesh nodes, organized in
a WMN, and at least one of the mesh nodes is wirelessly coupled to
the POP node. The WMN is a mesh topology in which the multiple mesh
nodes cooperate in distribution of the content files to client
consumption devices that do not have access to reliable access to
the server device of the CDN or in an environment of limited
connectivity to broadband infrastructure. A first node of the
multiple mesh nodes is a multi-radio, multi-channel (MRMC) device
that includes multiple P2P connections to form parts of a network
backbone in which the first node wireless connects to other mesh
nodes via a first set of WLAN channels reserved for inter-node
communication. The first node also includes one or more N2C
connections to wireless connect to one or more of the client
consumption devices connected to the WMN via a second set of WLAN
channels reserved for serving the content files to the client
consumption devices. The first node may also include a cellular
connection to wireless connect to a second device of the CDN. The
second device may be part of a cloud computing system and may host
a mesh network control service as described herein. It should be
noted that the first point-to-point connection is higher bandwidth
than the cellular connection.
FIG. 4A is a block diagram of a mesh network device 400 according
to one embodiment. The mesh network device 400 may be one of many
mesh network devices organized in a WMN (e.g., WMN 100). The mesh
network device 400 is one of the nodes in a mesh topology in which
the mesh network device 400 cooperates with other mesh network
devices in distribution of content files to client consumption
devices in an environment of limited connectivity to broadband
Internet infrastructure, as described herein. The mesh network
device 400 may be the mini-POP node 102 of FIG. 1. Alternatively,
the mesh network device 400 may be any one of the mesh network
devices 104-110 of FIG. 1. In another embodiment, the mesh network
device 400 is any one of the network hardware devices 202-210 of
FIG. 2. In another embodiment, the mesh network device 400 is the
mesh node 300 of FIG. 3.
The mesh network device 400 includes a system on chip (SoC) 402 to
process data signals in connection with communicating with other
mesh network devices and client consumption devices in the WMN. The
SoC 402 includes a processing element (e.g., a processor core, a
central processing unit, or multiple cores) that processes the data
signals and controls the radios to communicate with other devices
in the WMN. In one embodiment, the SoC 402 is a dual core SoC, such
as the ARM A15 1.5 GHz with hardware network acceleration. The SoC
402 may include memory and storage, such as 2 GB DDR RAM and 64 GB
eMMC coupled to the SoC 402 via external HDD interfaces (e.g.,
SATA, USB3, or the like). The SoC 402 may include multiple RF
interfaces, such as a first interface to the first RF module 404
(e.g., HSCI interface for cellular module (3G)), a second interface
to the WLAN 2.4 GHz radio 406, a third interface to the WLAN 2.4
GHz radio 408, and multiple interfaces to the WLAN 5 GHz radios,
such as on a PCIe bus. In one embodiment, the SoC 402 is the
IPQ8064 Qualcomm SoC or the IPQ4029 Qualcomm SoC. Alternatively,
other types of SoCs may be used, such as the Annapurna SoC, or the
like. Alternatively, the mesh network device 400 may include an
application processor that is not necessarily considered to be a
SoC.
The mesh network device 400 may also include memory and storage.
For example, the mesh network device 400 may include SSD 64 GB 428,
8 GB Flash 430, and 2 GB 432. The memory and storage may be coupled
to the SoC 402 via one or more interfaces, such as USB 3.0, SATA,
or SD interfaces. The mesh network device 400 may also include a
single Ethernet port 444 that is an ingress port for Internet
Protocol (IP) connection. The Ethernet port 444 is connected to the
Ethernet PHY 442, which is connected to the SoC 402. The Ethernet
port 444 can be used to service the mesh network device 400.
Although the Ethernet port 444 could provide wired connections to
client devices, the primary purpose of the Ethernet port 444 is not
to connect to client devices, since the 2.4 GHz connections are
used to connect to clients in the WMN. The mesh network device 400
may also include one or more debug ports 446, which are coupled to
the SoC 402. The memory and storage may be used to cache content,
as well as store software, firmware or other data for the mesh
network device 400.
The mesh network device 400 may also include a power management and
charging system 434. The power management and charging system 434
can be connected to a power supply 436 (e.g., 240V outlet, 120V
outlet, or the like). The power management and charging system 434
can also connect to a battery 438. The battery 438 can provide
power in the event of power loss. The power management and charging
system 434 can be configured to send a SoS message on power outage
and backup system state. For example, the WLAN radios can be
powered down, but the cellular radio can be powered by the battery
438 to send the SoS message. The battery 438 can provide limited
operations by the mesh network device 400, such as for 10 minutes
before the entire system is completely powered down. In some cases,
power outage will likely affect a geographic area in which the mesh
network device 400 is deployed (e.g., power outage that is a
neighborhood wide phenomenon). The best option may be to power down
the mesh network device 400 and let the cloud service (e.g., back
end service) know of the outage in the WMN. The power management
and charging system 434 may provide a 15V power supply up to 21
watts to the SoC 402. Alternatively, the mesh network device 400
may include more or less components to operate the multiple
antennas as described herein.
The mesh network device 400 includes a first radio frequency (RF)
module 404 coupled between the SoC 402 and a cellular antenna 418.
The first RF module 404 supports cellular connectivity using the
cellular antenna 418. In one embodiment, the cellular antenna 418
includes a primary wide area network (WAN) antenna element and a
secondary WAN antenna element. The first RF module 404 may include
a modem to cause the primary WAN antenna, the secondary WAN
antenna, or both to radiate electromagnetic energy in the 900 MHz
band and 1800 MHz band for the 2G specification, radiate
electromagnetic energy in the B1 band and the B8 band for the 3G
specification, and radiate electromagnetic energy for the B40 band.
The modem may support Cat3 band, 40 TD-LTE, UMTS: Band 1, Band 8,
and GSM: 900/1800. The modem may or may not support CDMA. The
cellular modem may be used for diagnostics, network management,
down time media caching, meta data download, or the like.
Alternatively, the first RF module 404 may support other bands, as
well as other cellular technologies. The mesh network device 400
may include a GPS antenna and corresponding GPS module to track the
location of the mesh network device 400, such as moves between
homes. However, the mesh network device 400 is intended to be
located inside a structure, the GPS antenna and module may not be
used in some embodiments.
The mesh network device 400 includes a first set of wireless local
area network (WLAN) modules 406, 408 coupled between the SoC 402
and dual-band omnidirectional antennas 420. A first WLAN module 406
may support WLAN connectivity in a first frequency range using one
of the dual-band omnidirectional antennas 420. A second WLAN module
408 may support WLAN connectivity in a second frequency range using
one of the dual-band omnidirectional antennas 420. The dual-band
omnidirectional antennas 420 may be two omnidirectional antennas
for 2.4 GHz. The directional antennas 422 may be eight sector
directional antennas for 5 GHz with two antennas at orthogonal
polarizations (horizontal/vertical) in each sector. These can be
setup with 45 degree 3 dB beam width with 11 dB antenna gain. The
dual-band omnidirectional antennas 420 and the directional antennas
422 can be implemented within a fully switchable antenna
architecture controlled by micro controller 426. For example, each
5 GHz radio can choose any 2 sectors (for 2 2.times.2 MU-MIMO
streams).
The mesh network device 400 includes a second set of WLAN modules
410-416 coupled between the SoC 402 and antenna switching circuitry
424. The second set of WLAN modules 410-416 support WLAN
connectivity in the second frequency range using a set of
directional antennas 422. The second set of WLAN modules 410-416 is
operable to communicate with the other mesh network devices of the
WMN. The antenna switching circuitry 424 is coupled to a micro
controller 426. The micro controller 426 controls the antenna
switching circuitry 424 to select different combinations of
antennas for wireless communications between the mesh network
device 400 and the other mesh network devices, the client
consumption devices, or both. For example, the micro controller 426
can select different combinations of the set of directional
antennas 422. The antenna switching circuitry 424 is described in
more detail below with respect to FIGS. 5-7.
In another embodiment, a filter switch bank is coupled between the
antenna switching circuitry 424 and the second set of WLAN modules
410-416. In another embodiment, the filter switch bank can be
implemented within the antenna switching circuitry 424.
In the depicted embodiment, the first set of WLAN modules include a
first a first 2.times.2 2.4 GHz MIMO radio 406 and a 2.times.2 5
GHz MIMO radio 408. The second set of WLAN modules includes a first
2.times.2 5 GHz MIMO radio 410 ("5GLL"), a second 2.times.2 5 GHz
MIMO radio 412 ("5GLH"), a third 2.times.2 5 GHz MIMO radio 414
("5GHL"), and a fourth 2.times.2 5 GHz MIMO radio 416 ("5GHH"). The
dual-band omnidirectional antennas 420 may include a first
omnidirectional antenna and a second omnidirectional antenna (not
individually illustrated in FIG. 4). The set of directional
antennas 422 comprises: a first horizontal orientation antenna; a
first vertical orientation antenna; a second horizontal orientation
antenna; a second vertical orientation antenna; a third horizontal
orientation antenna; a third vertical orientation antenna; a fourth
horizontal orientation antenna; a fourth vertical orientation
antenna; a fifth horizontal orientation antenna; a fifth vertical
orientation antenna; a sixth horizontal orientation antenna; a
sixth vertical orientation antenna; a seventh horizontal
orientation antenna; a seventh vertical orientation antenna; an
eighth horizontal orientation antenna; an eighth vertical
orientation antenna; a ninth antenna (upper antenna described
herein); a tenth antenna (upper antenna); an eleventh antenna
(bottom antenna); and a twelfth antenna (bottom antenna).
In one embodiment, the mesh network device 400 can handle antenna
switching in a static manner. The SoC 402 can perform sounding
operations with the WLAN radios to determine a switch
configuration. Switching is not done on a per packet basis or at a
packet level. The static switch configuration can be evaluated a
few times a day by the SoC 402. The SoC 402 can include the
intelligence for switching decision based on neighbor sounding
operations done by the SoC 402. The micro controller 426 can be
used to program the antenna switching circuitry 424 (e.g., switch
matrix) since the mesh network device 400 may be based on CSMA-CA,
not TDMA. Deciding where the data will be coming into the mesh
network device 400 is not known prior to receipt, so dynamic
switching may not add much benefit. It should also be noted that
network backbone issues, such as one of the mesh network devices
becoming unavailable, may trigger another neighbor sounding process
to determine a new switch configuration. Once the neighbor sounding
process is completed, the mesh network device 400 can adapt a beam
patter to be essentially fixed since the mesh network devices are
not intended to move once situated.
In one embodiment, the antenna switching circuitry 424 includes
multiple diplexers and switches to connect different combinations
of antennas to the multiple radios. FIGS. 5-7 illustrate three
different architectures for the antenna switching circuitry 424.
The following diagrams use the following notations for
reference:
ANT Hx.fwdarw.Horizontal orientation device side antenna
ANT Vx.fwdarw.Vertical orientation device side antenna
ANT VB.fwdarw.Vertical orientation device bottom side antenna
ANT HB.fwdarw.Horizontal orientation device bottom side antenna
ANT VU.fwdarw.Vertical orientation device top side antenna
ANT HU.fwdarw.Horizontal orientation device top side antenna
ANT0.fwdarw.Omni directional antenna
ANT1.fwdarw.Omni directional antenna
One configuration for the antenna switching circuitry 424 is a
switch matrix architecture. In this architecture, there are six
2.times.2 WLAN radios (also referred to as the Wi-Fi.RTM. radios).
Five radios are 5 GHz band and one radio is a 2.4 GHz radio. A
switch matrix is implemented to allow the connection of each and
any of the four 2.times.2 radios to any of the Vx/Hx MIMO antennas.
Based on the switch matrix configuration and based on the routing
algorithms input, each 2.times.2 radio can connect to a specific
antenna pair in a specific direction. Each 2.times.2 radio can
operate using a dedicated and unique WLAN frequency channel
concurrently or simultaneously. In this architecture, two of the
radios (5 GHz radio and 2.4 GHz radio) may have fixed connections
to the omnidirectional antennas (Ant0 and Ant1). These two radios
may also have access to all the WLAN 2.4 GHz and 5 GHz band
channels. In another embodiment, this architecture also may also
have 4G/3G and 2G WAN radio to provide cellular connectivity to the
mesh network device 400.
Conventional 2.4 GHz WLAN radio architectures can only operate on a
single channel while communicating to an access point (AP) or a
client device (e.g., client consumption devices described herein).
As a result, conventional solutions require spatially separated
multiple APs. One conventional solution uses techniques to improve
a receiver's adjacent channel interference (ACI) to address the
impact from congested 2.4 GHz environment. However, this
conventional solution supports only single channel operation in the
2.4 GHz band. FIGS. 5-12 are generally directed to embodiments of
the RFFE architecture with high selectivity performance. This
conventional solution does not address multi-radio operation in a
single device and also does not address transmit out-of-channel
noise (TXOON), which is a problem when multiple channels are
concurrently operating on the same device. The embodiments
described herein can be used to provide multi-radio operation in
the 2.4 GHz band, the 5 GHz band, as well as other frequency bands.
The embodiments described herein may also be used to improve
co-existence in multi-protocol radio applications, such as
Wi-Fi.RTM. and Zigbee.RTM. technologies, Wi-Fi.RTM. and
Bluetooth.RTM. technologies, implemented in a single device. The
embodiments described herein can be used to address TXOON caused by
multi-radio operation in a single device, as described in more
detail below. FIGS. 5-12 are generally directed to embodiments of
the RFFE architecture with high selectivity performance.
FIG. 5 is a block diagram of a RFFE circuit 500 with a programmable
filter circuit 510 according to various embodiments. In one
embodiment, the RFFE circuit 500 includes a first port 502
configured to be coupled to a transmitter (not illustrated in FIG.
5) and a second port 504 configured to be coupled to an antenna
(not illustrated in FIG. 5). The RFFE circuit 500 also includes a
local oscillator (LO) circuit 506 configured to generate a LO
signal 501. The LO circuit 506 may be a voltage controlled
oscillator (VCO), a phase locked loop (PLL) synthesizer, or other
types of frequency synthesizers or oscillators. Alternatively,
other LO circuits may be used. The RFFE circuit 500 includes a
first mixer 508 coupled to the LO circuit 506 and the first port
502. The first mixer 508 can be configured to receive the LO signal
501 from the LO circuit 506 and a transmit (TX) signal 503, having
a first frequency, from the first port 502. The first mixer 508
(also referred to as a frequency mixer, an up/down mixer) can be an
electrical circuit that creates a new signal from two input
signals. Mixers can be used to shift signals from one frequency
range to another. In this embodiment, the first mixer 508 down
converts the TX signals, but as described below, can up convert RX
signals. In the depicted embodiment, the first mixer 508 produces a
down-converted TX signal 505 for channel bandwidth filtering. The
TX signal 503 has a second frequency that is lower than the first
frequency. The RFFE circuit 500 includes a programmable filter
circuit 510 coupled to the first mixer 508. The programmable filter
circuit 510 can receive a selection signal (not illustrated in FIG.
5), and in response to the selection signal, filter the
down-converted TX signal 505, according to a selected channel
bandwidth per the selection signal, to produce a channel-filtered
TX signal 507 corresponding to the selected channel bandwidth. The
selected channel bandwidth may be one of multiple channel
bandwidths in a single frequency band (e.g., four channel
bandwidths for the WLAN frequency band, such as 2.4 GHz band). The
RFFE circuit 500 includes a second mixer 512 that is coupled to the
LO circuit 506 and the programmable filter circuit 510. The second
mixer 512 is configured to receive the LO signal 501 from the LO
circuit 506 and the channel-filtered TX signal 507 from the
programmable filter circuit 510 and produce an up-converted TX
signal 509 having the first frequency. The RFFE circuit 500
includes a power amplifier 514 that is coupled to the second mixer
512. The power amplifier 514 is configured to amplify the
up-converted TX signal 509 to produce an output TX signal 511 on
the second port 504. The output TX signal 511 causes the antenna to
radiate electromagnetic energy in the selected channel
bandwidth.
In a further embodiment, the RFFE circuit 500 also includes a third
port 516 configured to be coupled to a receiver (not illustrated in
FIG. 5) and a low-noise amplifier (LNA) 518 coupled to the second
port 504. The LNA 518 is configured to receive a RX signal 513
having a third frequency in the frequency band from the second port
504, via the antenna. The LNA 518 amplifies the RX signal 513 to
produce a filtered RX signal 515. The second mixer 512 is coupled
to the LNA 518 and is further configured to receive the LO signal
501 and the filtered RX signal 515 and produce a down-converted RX
signal 517 for channel bandwidth filtering by the programmable
filter circuit 510. The down-converted RX signal 517 has a fourth
frequency that is lower than the third frequency. The programmable
filter circuit 510, in response to a second selection signal, is
configured to filter the down-converted RX signal 517 according to
a second selected channel bandwidth to produce a channel-filtered
RX signal 519 corresponding to the second selected channel
bandwidth. The first mixer 508 is further configured to receive the
LO signal 501 and the channel-filtered RX signal 519 to produce an
up-converted RX signal 521 on the third port. The up-converted RX
signal 521 has the third frequency.
In one embodiment, the first port 502 is coupled to a first port
502 of a radio and the third port 516 is coupled to a second port
of the radio. The radio may include both the transmitter and the
receiver. In one embodiment, the RFFE circuit 500 is a first
integrated circuit and the radio is a second integrated circuit
that is different than the first integrated circuit. Alternatively,
the RFFE circuit 500 may be integrated with the radio, a processing
device, or other circuitry of an electronic device. In one
embodiment, the RFFE circuit 500 is part of the SoC 402 of FIG. 4.
Alternatively, the RFFE circuit 500 is part of the antenna
switching circuitry 424 of FIG. 4, part of the microcontroller of
FIG. 4, or part of other components of the mesh network device 400
of FIG. 4. Alternatively, the RFFE circuit 500 can be implemented
in other electronic devices than the mesh network devices described
herein.
In another embodiment, as illustrated in dashed lines of FIG. 5,
the RFFE circuit 500 further includes a fourth port 532 configured
to be coupled to a second transmitter (not illustrated in FIG. 5),
a fifth port 534 configured to be coupled to a second antenna not
illustrated in FIG. 5), a sixth port 536 configured to be coupled
to a second receiver not illustrated in FIG. 5), a duplicate
circuit 530 coupled the fourth port 532, the fifth port 534, and
the sixth port 536. The duplicate circuit 530 can include the same
components as those described above, for example, including a
second LO circuit, a third mixer, a second programmable filter
circuit, a fourth mixer, a second power amplifier, and a second
LNA. The second transmitter and the second receiver may be
integrated into a same second radio, whereas the transmitter and
receiver coupled to the ports 502, 516, respectively are integrated
into a same first radio. The two radios can be implemented in a
single integrated circuit or multiple integrated circuits. For
example, the RFFE circuit 500 is a first integrated circuit, the
first radio is a second integrated circuit that is different than
the first integrated circuit, and the second radio is a third
integrated circuit that is different than the first integrated
circuit and the second integrated circuit. The RFFE circuit 500 may
also be implemented in more than one integrated circuit.
In one embodiment, the second LO circuit is configured to generate
a second LO signal. The frequency of the second LO signal can be
the same or different than the frequency of the LO signal described
above with respect to the first radio and first antenna. The third
mixer is configured to receive the second LO signal from the second
LO circuit and a second TX signal from the fourth port 532 and
produce a second down-converted TX signal for channel bandwidth
filtering by the second programmable filter circuit. The second TX
signal has a sixth frequency. The sixth frequency can be the same
or different than the second frequency described above with respect
to the first radio and first antenna. The second programmable
filter circuit, in response to a third selection signal, is
configured to filter the second down-converted TX signal according
to a third selected channel bandwidth to produce a second
channel-filtered TX signal corresponding to the third selected
channel bandwidth. The fourth mixer is configured to receive the
second LO signal from the second LO circuit and the second
channel-filtered TX signal from the second programmable filter
circuit and produce a second up-converted TX signal having the
fifth frequency. The second power amplifier is configured to
amplify the second up-converted TX signal to produce a second
output TX signal on the fifth port 534. The second output TX signal
causes a second antenna to radiate electromagnetic energy in the
third selected channel bandwidth.
In a further embodiment, the second LNA is configured to filter a
second RX signal having a seventh frequency, received via the
second antenna, to produce a second filtered RX signal. The seventh
frequency may be the same or different frequency as the third
frequency described above with respect to the first radio and the
first antenna. The fourth mixer is further configured to receive
the second LO signal and the second filtered RX signal and produce
a second down-converted RX signal for channel bandwidth filtering
by the second programmable filter circuit. The second
down-converted RX signal has an eighth frequency that is lower than
the third frequency. The eighth frequency can be the same or
different than the fourth frequency described above with respect to
the first radio and first antenna. The second programmable filter
circuit, in response to a fourth selection signal, is configured to
filter the second down-converted RX signal according to a fourth
selected channel bandwidth to produce a second channel-filtered RX
signal corresponding to the fourth selected channel bandwidth. The
third mixer is further configured to receive the second LO signal
and the second channel-filtered RX signal to produce a second
up-converted RX signal on the sixth port 536. The second
up-converted RX signal has the third frequency.
In one embodiment, as illustrated in FIGS. 6A, 6B, and 7, the
programmable filter circuit 510 includes a first multi-port switch
coupled to the first mixer 508 and a second multi-port switch
coupled to the second mixer 512. The first multi-port switch is
configured to receive the down-converted TX signal from the first
mixer and the selection signal. The second multi-port switch is
configured to receive the channel-filtered TX signal from the
programmable filter circuit 510 and the selection signal. The
programmable filter circuit 510 also includes a first channel band
pass filter (BPF) disposed along a first channel path between the
first multi-port switch and the second multi-port switch and a
second channel BPF disposed along a second channel path between the
first multi-port switch and the second multi-port switch. The first
channel BPF is configured to filter the down-converted TX signal
according to a first channel bandwidth to produce the
channel-filtered TX signal corresponding to the selected channel
bandwidth. The second channel BPF is configured to filter the
down-converted TX signal according to a second channel bandwidth to
produce the channel-filtered TX signal corresponding to the
selected channel bandwidth. In a further embodiment, the
programmable filter circuit 510 further includes a third channel
BPF disposed along a third channel path between the first
multi-port switch and the second multi-port switch and a fourth
channel BPF disposed along a fourth channel between the first
multi-port switch and the second multi-port switch. The third
channel BPF is configured to filter the down-converted TX signal
according to a third channel bandwidth to produce the
channel-filtered TX signal corresponding to the selected channel
bandwidth. The fourth channel BPF is configured to filter the
down-converted TX signal according to a fourth channel bandwidth to
produce the channel-filtered TX signal corresponding to the
selected channel bandwidth.
The RFFE circuit 500 can be implemented using various circuit
configurations, such as illustrated and described below with
respect to FIGS. 6A, 6B, and 7.
FIG. 6A is a block diagram of a transmit (TX) path within RFFE
circuitry 600 with high selectivity performance in multi-channel
operation according to one embodiment. The RFFE circuitry 600
includes a first port 602 coupled to a transmitter of radio 620, a
second port 604 coupled to a first antenna 630, and a third port
616 coupled to a receiver of the radio 620. In one embodiment, the
radio 620 is a WLAN radio, such as a radio implementing the
Wi-Fi.RTM. technology in the 2.4 GHz band, the 5 GHz band, or any
combination thereof. The radio 620 may also be other types of
radios, such as wireless PAN radios, cellular radios, or the like.
The RFFE circuitry 600 also includes similar components as the RFFE
circuit 500 of FIG. 5, as noted by similar reference numbers. For
example, the RFFE circuitry 600 includes a LO circuit 606, a first
mixer 608, a programmable filter circuit 610, a second mixer 612, a
power amplifier 614, and a LNA 618 that operate in a similar
fashion as described above with respect to FIG. 5. The RFFE
circuitry 600 includes additional components as described in more
detail below.
In the depicted embodiment, the RFFE circuitry 600 includes a first
driver amplifier (DA) 632 coupled to the first port 602 and a first
BPF 634 coupled to the first DA 632 and the first mixer 608. The
first DA 632 amplifies a TX signal 603 received from the first port
602 (also referred to as a transmitter port) to produce an
amplified TX signal. The transmit TX signal 603 has a RF frequency
within a first frequency range. The first BPF 634 filters the
amplified TX signal to produce a filtered TX signal that is input
into the first mixer 608. The first DA 632 and the first BPF 634
can be implemented in a block circuit with a first switch 636 to
accommodate a TX path from the transmitter and a RX path to the
receiver. The RX path is described below with respect to FIG.
6B.
The RFFE circuitry 600 also includes a second BPF 638 coupled to
the LO circuit 606 and a second DA 640 coupled to the second BPF
and the first mixer 608. The second BPF 638 filters the LO signal
601 to produce a filtered LO signal. The second DA amplifies the
filtered LO signal to produce an amplified LO signal that is input
into the first mixer 608. The first mixer 608 receives the
amplified LO signal and the filtered TX signal to produce an
intermediate frequency (IF) TX signal 605 (down-converted TX signal
605) with an intermediate frequency (IF) that is lower than the
first frequency of the TX signal 603.
The RFFE circuitry 600 also includes a third DA 642 that is coupled
to the first mixer 608. The third DA 642 can be implemented in a
block circuit with a second switch 644 and a third switch 646 to
accommodate the TX path and the RX path to the receiver. The RX
path may include a DA as well as is described below with respect to
FIG. 6B.
The RFFE circuitry 600 also includes a third BPF 648 that is
coupled to the LO circuit 606 and a fourth DA 650 that is coupled
to the third BPF 648 and the second mixer 612. The third BPF 648
filters the LO signal 601 to produce a second filtered LO signal
and the fourth DA 650 amplifies the second filtered LO signal to
produce a second amplified LO signal that is input into the second
mixer 612. The second mixer 612 receives the second amplified LO
signal and a second signal 607 that is one of the four filtered IF
TX signals as described below (also referred to as the
channel-filtered TX signal 607). The second mixer 612 produces an
up-converted TX signal 609 having the RF frequency.
The RFFE circuitry 600 also includes a fourth BPF 652 coupled to
the second mixer 612 and the power amplifier 614. The fourth BPF
652 filters the up-converted TX signal 609 to produce a filtered,
up-converted TX signal. The power amplifier 614 amplifies the
filtered, up-converted TX signal to produce an output TX signal
611. The output TX signal 611 causes the antenna 630 to radiate
electromagnetic energy in the first frequency range. The fourth BPF
652 can be implemented in a block circuit with a fourth switch 654
and a fifth switch 656 to accommodate the TX path and the RX path.
The RX path may include a LNA 618 and a fifth BPF 658, which are
described below with respect to FIG. 6B. In another embodiment, a
power detector 660 is coupled to the power amplifier 614 and feeds
back to the radios 620 the power detected. In one embodiment, the
power detector 660 is a RF coupler. Alternatively, other circuits
could be used to detect and report the power of the output TX
signal 611.
In the depicted embodiment, the programmable filter circuit 610
includes a first multi-port switch 662 coupled to the third DA 642,
via the third switch 646, and a second multi-port switch 664
coupled to the second mixer 612. The first multi-port switch 662 is
configured to receive the down-converted TX signal 605 from the
first mixer 608. The first multi-port switch 662 also receives a
selection signal (not illustrated in FIG. 6A). The selection signal
may be received from the radio 620. Alternatively, the selection
signal may be received from another component, such as the SoC, the
antenna switching circuitry, or the microcontroller, as described
herein. The programmable filter circuit 610 also includes multiple
channel BPFs 666. In the depicted embodiment, the programmable
filter circuit 610 includes four channel BPFs 666, including a
first channel BPF disposed along a first channel path between the
first multi-port switch 662 and the second multi-port switch 664; a
second channel BPF disposed along a second channel path between the
second multi-port switch and the second multi-port switch; a third
channel BPF disposed along a third channel path between the first
multi-port switch and the second multi-port switch; and a fourth
channel BPF disposed along a fourth channel path between the second
multi-port switch and the second multi-port switch. The first
channel BPF is configured to filter the down-converted TX signal
605 according to a first channel bandwidth (e.g., 40 MHz) to
produce the channel-filtered TX signal 607 corresponding to the
selected channel bandwidth. The second channel BPF is configured to
filter the down-converted TX signal 605 according to a second
channel bandwidth (e.g., 80 MHz) to produce the channel-filtered TX
signal 607 corresponding to the selected channel bandwidth. The
third channel BPF is configured to filter the down-converted TX
signal 605 according to a third channel bandwidth to produce the
channel-filtered TX signal 607 corresponding to the selected
channel bandwidth. The fourth channel BPF is configured to filter
the down-converted TX signal 605 according to a fourth channel
bandwidth to produce the channel-filtered TX signal 607
corresponding to the selected channel bandwidth.
In the depicted embodiment, the LO circuit 606 includes a frequency
synthesizer 668 and a 2-way divider 670. The frequency synthesizer
668 can be a voltage controlled oscillator (VCO) and can receive a
control signal 669 from the radio 620. In one embodiment, the radio
620 operates in the 2.4 GHz band and the frequency synthesizer 668
can generate the LO signal 601 with the second frequency that is
within a frequency range between approximately 2038 MHz and 2098
MHz. In one implementation, the second frequency is 2063 MHz. The
2-way divider 670 can create two copies of the LO signal 601, a
first copy of the LO signal 601 being fed to the first mixer 608
and a second copy of the LO signal 601 being fed to the second
mixer 612. Alternatively, the LO circuit 606 may be other types of
local oscillators.
In one embodiment, the radio 620 is a WLAN radio that operates at
2.4 GHz for wireless communications using any one of the WLAN
protocols, such as 802.11n. The WLAN radio includes a zero
intermediate frequency (ZIF) transceiver that transmits a RF signal
using channel 6, according to any one of the wireless protocols,
such as the 802.11a/b/g/n/ac Wi-Fi.RTM. standards. ZIF architecture
is also referred to as direct conversion architecture (DCR). DCR or
ZIF architectures can be used because of its simplicity and low
cost. Most ZIF transmitters/transceivers do not have inter-stage
filters. Because of less filtering, the linearity requirement for a
direct conversion receiver is important as it is more sensitive
than super-heterodyne architectures. In full duplex division, a
strong TX signal can create unwanted input at a LNA of a receiver,
causing non-linearity. This is also referred to as TX blocking. In
this example, the RF signal may have a center frequency of 2436
MHz. The RFFE circuitry may include a driver amplifier, two-way
switch, and an RF band pass filter may be coupled to a transmitter
port of the WLAN radio, a down-converter mixer is connected to the
filter output and converts the RF signal to an intermediate
frequency (IF) TX signal (e.g., 374 MHz). The IF TX signal is
passed to a switch and a driver amplifier. A synthesizer is used to
generate a desired LO signal. The LO frequency range, for example,
may be approximately 2038 MHz to 2098 MHz. The LO signal passes
through an LO band pass filter and a driver amplifier and is fed
into the down-converter mixer. The down-converter mixer produces an
IF TX signal with the designed intermediate frequency. The IF
signal is amplified by an IF driver amplifier and connected to a
4-port switch, which selects and routes the IF signal to the
selected IF channel BPF. For example, the RFFE can include several
different channel filters, for example, a channel filter for 20
MHz, a channel filter for 40 MHz, a channel filter for 80 MHz,
respectively. This different channel filters can be used to
accommodate different channel bandwidth configurations defined by
the protocol. The IF filtered IF signal is passed to an
up-converter mixer that up-converts the signal to the original RF
frequency. A similar stage of LO, DA, and filter is used to feed
the LO signal to the up-converter mixer, as done for the
down-converter mixer. The up-converted TX signal is fed to an RF
band pass filter, switch, and power amplifier. The TX signal is
passed to the antenna for over the air transmission.
In another embodiment, an electronic device includes a first
antenna, a first zero ZIF transceiver including a transmitter port;
and RFFE circuitry coupled to the first ZIF transceiver and the
first antenna. The RFFE circuitry includes a first DA coupled to
the transmitter port and a frequency synthesizer generates a LO
signal. The first DA amplifies a TX signal received from the
transmitter port to produce an amplified TX signal having a RF
frequency within a first frequency range. A first BPF is coupled to
the first DA and the first BPF filters the amplified TX signal to
produce a filtered TX signal. A first mixer is coupled to the first
BPF and a second BPF is coupled to the frequency synthesizer. The
second BPF filters the LO signal to produce a filtered LO signal. A
second DA is coupled to the second BPF and the first mixer. The
second DA amplifies the filtered LO signal to produce an amplified
LO signal. The first mixer receives the amplified LO signal and the
filtered TX signal to produce an IF TX signal with an intermediate
frequency (e.g., 374 MHz). The intermediate frequency may be lower
than the RF frequency. A third DA is coupled to the first mixer and
the third DA amplifies the IF TX signal to produce an amplified IF
TX signal. The RFFE includes a first multi-port switch that is
coupled to the third DA, a second multi-port switch, a first
channel BPF and a second channel BPF. The first channel BPF is
coupled between a first port of the first multi-port switch and a
first port of the second multi-port switch on a first channel path.
The second channel BPF is coupled between a second port of the
first multi-port-switch and a second port of the second multi-port
switch. The first channel BPF filters the amplified IF TX signal to
produce a first filtered IF TX signal when the first port of the
first multi-port switch and the first port of the second multi-port
switch are selected for a first channel bandwidth of the first
frequency range. The second channel BPF filters the amplified IF TX
signal to produce a second filtered IF TX signal when the second
port of the first multi-port switch and the second port of the
second multi-port switch are selected for a second channel
bandwidth of the first frequency range. A third BPF is coupled to
the frequency synthesizer and the third BPF filters the LO signal
to produce a second filtered LO signal. A fourth DA is coupled to
the third BPF and the fourth DA amplifies the second filtered LO
signal to produce a second amplified LO signal that is fed into the
second mixer. The second mixer receives the second amplified LO
signal and either the first filtered IF TX signal or the second
filtered IF TX signal to produce an up-converted TX signal with the
RF frequency. A fourth BPF is coupled to the second mixer and the
fourth BPF filters the up-converted TX signal to produce a
filtered, up-converted TX signal. A power amplifier is coupled to
the fourth BPF and the first antenna. The power amplifier amplifies
the filtered, up-converted TX signal to produce an output TX signal
to cause the first antenna to radiate electromagnetic energy with
either a selected one of the first channel bandwidth or the second
channel bandwidth.
In another embodiment, the ZIF transceiver also includes a receiver
and the RFFE is coupled to a receiver port. The RFFE circuitry
further includes a first switch coupled to the receiver port, the
transmitter port, and the first BPF. The first DA is coupled
between the transmitter port and the first switch. The RFFE circuit
also includes a fifth DA, a second switch coupled to the first
mixer and a third switch coupled to the first multi-port switch.
The third DA is disposed along a TX path between the second switch
and the third switch and the fifth DA is disposed along a RX path
between the second switch and the third switch. A LNA is coupled to
the fifth BPF and the fifth BPF filters a RX signal received by the
first antenna to produce a filtered RX signal. The LNA amplifies
the filtered RX signal to produce an amplified RX signal. The RFFE
circuit further includes a fourth switch coupled to the fourth BPF
and a fifth switch coupled to the antenna. The LNA and the fifth
BPF are disposed along a TX path between the fourth switch and the
fifth switch and the power amplifier is disposed along a RX path
between the fourth switch and the fifth switch. The fourth BPF
filters the amplified RX signal to produce a filtered RX signal.
The second mixer receives the second amplified LO signal and the
filtered RX signal to produce an IF RX signal with the intermediate
frequency. The first channel BPF filters the IF RX signal to
produce a first filtered IF RX signal when the first channel path
is selected and the second channel BPF filters the IF RX signal to
produce a second filtered IF RX signal when the second channel path
is selected. The fifth DA amplifies either the first filtered IF RX
signal or the second filtered IF RX signal to produce an amplified
IF RX signal. The first mixer receives the amplified LO signal and
the amplified IF RX signal to produce an up-converted TX signal
with the RF frequency. The first BPF filters the up-converted TX
signal to produce an input RX signal for the receiver port.
In a further embodiment, the RFFE circuitry further includes a
third channel BPF and a fourth channel BPF. The third BPF is
coupled between a third port of the first multi-port switch and a
third port of the second multi-port switch in a third channel path
and the fourth channel BPF is coupled between a fourth port of the
first multi-port switch and a fourth port of the second multi-port
switch in a fourth channel path.
FIG. 6B is a block diagram of a receive (RX) path within the RFFE
circuitry 600 of FIG. 6A according to one embodiment. The RFFE
circuitry 600 includes the components described above with respect
to FIG. 6A, as well as some additional components described herein.
The RFFE circuitry 600 further includes a third port 616 coupled to
a receiver of the radio 620. A first switch 636 is coupled to the
first port 502, the third port 616, and the first BPF 634. The
first DA 632 is coupled between the first port 502 and the first
switch 636. The RFFE circuitry 600 further includes a second switch
644 coupled to the first mixer 508 and a third switch 646 coupled
to the programmable filter circuit 610. The third DA 642 is
disposed along a TX path between the second switch 644 and the
third switch 646. A fifth DA 672 is disposed along a RX path
between the second switch 644 and the third switch 646. A fifth BPF
658 is coupled to the second mixer 612 and the fifth BPF filters
658 a RX signal 621 received by the first antenna 630 to produce a
filtered RX signal 623. An LNA 618 amplifies the filtered RX signal
623 to produce an amplified RX signal 625. A fourth switch 654 is
coupled to the fourth BPF 652 and a fifth switch 656 is coupled to
the second port 604. The LNA 618 and the fifth BPF 658 are disposed
along a TX path between the fourth switch 654 and the fifth switch
656 and the power amplifier 614 is disposed along a RX path between
the fourth switch 654 and the fifth switch 656. The fourth BPF
filter 652 the amplified RX signal 625 to produce a filtered RX
signal 627 and the second mixer 612 receives the second amplified
LO signal and the filtered RX signal 627 to produce an IF RX signal
629 with the intermediate frequency. The fifth DA 672 amplifies
either the first filtered IF RX signal or the second filtered IF RX
signal to produce an amplified IF RX signal 631. The first mixer
608 receives the amplified LO signal and the amplified IF RX signal
631 to produce an up-converted TX signal 633 with the RF frequency
and the first BPF filters the up-converted TX signal 633 to produce
an input RX signal 635 for the third port 616 (receiver port).
In one embodiment, the radio 620 is a WLAN radio that operates at
2.4 GHz for wireless communications using any one of the WLAN
protocols, such as 802.11n. The WLAN radio includes a ZIF
transceiver that receives a RF signal using channel 6, according to
any one of the wireless protocols, such as the 802.11a/b/g/n/ac
Wi-Fi.RTM. standards. The RF signal may have a center frequency of
2436 MHz. During operation of the RFFE circuitry 600, a RX signal
is received at the first antenna 630 from over the air
transmission. The RX signal may be passed to an LNA, BPF and
switch. A down-converter mixer can down convert the signal to the
original intermediate frequency. Similar DA and filter stages are
used to feed the LO signal to the mixer similar to the down
converter mixer. The IF RX signal is filtered through the switch
and IF BPF. The programmable filter circuit may include multiple
channel filters with 20 MHz, 40 MHz, and 80 MHz respectively to
support different channel bandwidth configurations defined by the
standard. The filtered IF Rx signal is passed through a switch to
an IF driver amplifier and the IF Rx signal is up converted to the
RF frequency through the up-converter mixer. The RF Rx signal is
passed to an RF BPF then to a switch to route the signal to the RX
path of the radio 620.
In another embodiment, the electronic device further includes a
second antenna, a second ZIF transceiver, including a second
transmitter port and a second receiver port, and second RFFE
circuitry coupled between the second antenna and the second
transmitter port and the second receiver port of the second ZIF
transceiver. The second RFFE circuitry is a duplicate of the RFFE
circuitry described above. For example, the electronic device may
include a first radio coupled to a first antenna via first RFFE
circuitry and a second radio coupled to a second antenna via second
RFFE circuitry, such as illustrated in FIG. 7. The following
description describes a bi-directional RFFE radio architecture with
multiple channels for concurrent radio operation with high
selectivity performance. The embodiments described herein may allow
for more than a single-channel radio operation with conventional
antenna isolation architectures at the 2.4 GHz band. Other
embodiments may allow more than four channels concurrent operation
with conventional antennas isolation architecture at the 5 GHz
band. The embodiments described herein may increase capacity, for
example, proportionally increase data throughput followed by
numbers of radios. The embodiments described herein may have lower
TXOON as compared to traditional ZIF transceivers without the RFFE
circuitry described herein. The embodiments described herein may
improve the selectivity (ACI and CCI) on the receiver. The
embodiments described herein may support multiple channels
M.times.N MIMO Radio, where M is the number of transmitters on a
first device (e.g., at an access point or base station) and N is
the number of transmitters on a second device (e.g., client
consumption device, STA, or the like), where M and N are positive
integers.
FIG. 7 is a block diagram of RFFE circuitry 700 with high
selectivity performance in multi-channel operation with multiple
radios and multiple antennas according to one embodiment. The RFFE
circuitry 700 includes the RFFE circuitry 600 of FIGS. 6A and 6B
and further includes N number of duplicate RFFE circuits for each
of N radios, where N is a positive integer greater than 1. The
depicted embodiment, for simplicity, illustrates one duplicate RFFE
circuit 710. The duplicate RFFE circuit 710 is coupled between an
Nth radio 720 and an Nth antenna 730. The duplicate RFFE circuit
710 may include the same components as described above with respect
to RFFE circuitry 600 as described above with respect to FIGS. 6A
and 6B. Similarly, the duplicate RFFE circuit 710 operates in a
similar fashion in both the transmit path and receive path as the
RFFE circuitry 600.
FIG. 8 is a graph 800 showing a transmit out-of-channel noise
(TXOON) with RFFE circuitry of FIG. 7 according to one embodiment.
The graph 800 shows the RX signal 802, the TXOON 804 when using a
ZIF transceiver with the RFFE circuitry 700 of FIG. 7 and the TXOON
806 when using a ZIF transceiver without the RFFE circuitry 700
according to one embodiment. For measuring TXOON, the ZIF
transceiver is set to transmit in channel 6 and receive in channel
1 in the 2.4 GHz band for IEEE 802.11n is used with a coding scheme
of MCS7 with long guard interval (LGI) for the coding information.
This may be the standard setting for IEEE 802.11n (compared to SGI
400 ns). Channel 1 is at 2412 MHz, Channel 6 is at 2437 MHz,
Channel 10 is at 2457 MHz, and channel 11 is at 2462 MHz. The
channel bandwidth of 20 MHz is selected for the ZIF transceiver.
The TXOON is the transmit power by a transmitter of the ZIF
transceiver in frequencies outside of the channel selected for
receiving the RX signal. In this case, the RX signal 802 is
received in Channel 1 at 2412 MHz with a 20 MHz channel bandwidth
and a transmitter of the ZIF transceiver is transmitting in Channel
6 at 2437 MHz with a 20 MHz channel bandwidth. As a result of
transmitting in Channel 6, there is TXOON that affects the
receiving of the RX signal. To permit concurrent operation of
transmitting in Channel 6 while receiving in Channel 1, the RFFE
circuitry 700 is designed to have an antenna requirement for the
receiver that is less than -160 dBm/Hz at both at Channel 1 at 2412
MHz and Channel 11 at 2462 MHz. Thus, the RFFE circuitry 700 can be
designed to have a TXOON at the receiver less -140 dBm/Hz with
antenna isolation of approximately -30 dBM/Hz. As illustrated in
FIG. 8, the TXOON 806 is higher than TXOON 804 at Channel 1 at 2412
MHz and Channel 11 at 2462 MHz. The following table illustrates the
TXOON at three other channels of the ZIF transceiver when the ZIF
transceiver is transmitting in channel 6 with and without the RFFE
circuitry 700.
TABLE-US-00001 Without RFFE With RFFE circuitry 700 circuitry 700
TX Power/Channel 6 10 dBm 10 dBm (2437 MHz) TXOON at channel 1
-107.9 dBm/Hz -142.6 dBm/Hz (2412 MHz) TXOON at channel 10 -100.8
dBm/Hz -129.7 dBm/Hz (2457 MHz) TXOON at channel 11 -10769 dBm/Hz
-143.3 dBm/Hz (2462 MHz)
As illustrated in FIG. 8, the TXOON 804 tapers quicker in TX power
once outside of the selected channel (e.g., Channel 6) for
transmitting than TXOON 806. That is using the RFFE circuitry 700
with the ZIF transceiver reduces the TXOON 804 in the other
channels more effectively than a ZIF transceiver without the RFFE
circuitry 700.
FIG. 9 is a block diagram of two radios that operate in two
channels at the same time within a single band according to one
embodiment. In this embodiment, a first electronic device, such as
a wireless access point (AP), includes a radio 902 with a
transmitter that transmits at a first channel (e.g., channel 1 in
2.4 GHz band) and a receiver that receives at channel a second
channel (e.g., channel 6 in 2.4 GHz band). A second electronic
device, such as a station (STA), includes a radio 904 with a
transmitter that transmits in the second channel (e.g., channel 6)
and a receiver that receives at the first channel (e.g., channel
1). The two radios of the two devices can operate in a single band
(e.g., 2.4 GHz band) and can communicate with two channels (e.g.,
channel 1 and 6) at the same time in a frequency division duplex
(FDD) fashion. FDD is a technique where separate frequency bands
are used at the transmitter and receiver so the sending and
receiving of signals do not interfere with each other. Given the
proximity of the channels in the 2.4 GHz band, the TXOON caused by
the transmitter in one channel needs to be reduced for the receiver
in the other channel. The embodiments of the RFFE circuitry as
described herein reduces the TXOON as illustrated in graph 906 of
FIG. 9. The transmitter of radio 902 transmits a TX signal 908, via
an antenna 910, and a corresponding RX signal 912 is received by
the receiver of radio 904 via antenna 914. For example, the
transmit signal may be 10 dBm per the channel bandwidth at channel
6 at 2437 MHz at an antenna port of antenna 910 of radio 902.
However, the first device's radio 902 transmission on channel 6
impacts the TXOON on channel 1 bandwidth at the receiver of radio
904 of the second device. The TXOON from channel 6 to channel 1 can
cause a de-sense on the receiver. When the radio 902 transmits via
the antenna 910, the TX power at channel 6 generates the power
spectrum illustrated in FIG. 8 at channel 1. The power generated in
channel 1 will be received by the radio 904 at channel 1 via the
antenna 914, hence causing a de-sense of the radio 904. This is
illustrates in the hashed region 918 of graph 906. To avoid or
reduce the de-sense on the receiver, the first device's radio 902
should have TXOON less than an equivalent noise floor on the
receiver. In some cases, the target TXOON may be less than -140
dBm/Hz. By adding a 30 dB isolation between the radio 902 and radio
904, the de-sense on the receiver can be further reduced or avoided
to achieve less than -160 dBm/Hz for the receiver antenna
requirement. For example, as illustrated and described above, using
the RFFE circuitry 700, the TXOON at channel 1 can be -142 dBm/Hz.
With 30 dBm antenna isolation, the TXOON becomes -172 dBm/Hz at
channel 1 at the receiver of radio 904. This permits the first
device and the second device to communicate on two channels (e.g.,
channel 1 and 6) at the same time without de-sense on the
receiver.
FIG. 10 is a graph 1000 showing a baseband spectrum of the ZIF
transceiver with and without the RFFE circuitry according to one
embodiment. The graph 1000 shows RX power for RX signals 1002
received when using the RFFE circuitry described herein and RX
signals 1004 received when not using the RFFE circuitry described
herein. For this simulation, the radios communicate in two channels
in the 2.4 GHz band according to IEEE 802.11n with MCS7 with LGI
coding information. The channel bandwidth is 20 MHz, the
transmitter (aggressor) of the first radio transmits on channel 6
and the receiver (victim) of the second radio receives on channel
1. For the simulation, the aggressor's TX power is swept from -60
dBm/channel bandwidth (chBW) to -10 dBm/chBW. FIG. 10 shows a
linearity improvement with -50 dBm/chBW at channel 6 comparing the
ZIF transceiver architecture with and without the RFFE circuitry as
described herein. As illustrated in FIG. 10, there is signal
distortion 1006 in the RX signals caused by adjacent channel
interference (ACI). As illustrated in FIG. 10, the signal
distortion in the RX signals 1002 is less than the signal
distortion in RX signals 1004. There is also a 21 dB improvement on
packet error rate at 10 percent when using an architecture with the
RFFE circuitry as compared to the architecture without the RFFE
circuitry, as illustrated in FIG. 11.
FIG. 11 is a graph 1100 showing packet error rate (PER) as a
function of the ACI power of the ZIF transceiver with and without
the RFFE circuitry according to one embodiment. At ten percent, a
PER 1102 of an architecture without the RFFE circuitry is
approximately -46 dBm in ACI power, whereas a PER 1104 of an
architecture with the RFFE circuitry is approximately -25 dBm in
ACI power, resulting in an improvement of 21 dBm in PER.
As described above and illustrated with respect to FIG. 9, a
de-sense can be caused by TXOON. Similarly, ACI or alternative ACI
(AACI) can cause a de-sense at the receiver. The RFFE described
herein may also prevent a de-sense from ACI or AACI, as illustrated
in FIG. 12.
FIG. 12 is a block diagram of two radios that operate in two
channels at the same time within a single band according to another
embodiment. In this embodiment, a first electronic device, such as
a wireless access point (AP), includes a radio 1202 with a
transmitter that transmits at a first channel (e.g., channel 1 in
2.4 GHz band) and a receiver that receives at channel a second
channel (e.g., channel 6 in 2.4 GHz band). A second electronic
device, such as a station (STA), includes a radio 1204 with a
transmitter that transmits in the second channel (e.g., channel 6)
and a receiver that receives at the first channel (e.g., channel
1). The two radios of the two devices can operate in a single band
(e.g., 2.4 GHz band) and can communicate with two channels (e.g.,
channel 1 and 6) at the same time in a FDD fashion. Given the ACI,
-142 dBm/Hz from channel 6 falls into channel 1 (the overlapped
area between an incoming signal 1208 from channel 6 of radio 1202
and a wanted RX signal 1212), the receiver can be affected by the
TX power, causing non-linearity. The embodiments of the RFFE
circuitry as described herein reduces the ACI as illustrated in
graph 1206 of FIG. 12. The transmitter of radio 1202 transmits a TX
signal, via an antenna 1210, and a corresponding RX signal 1212 is
received by the receiver of radio 1204 via antenna 1214. More
specifically, when the radio 1202 transmits TX power at channel 6
via the antenna 910, the power will be received by radio 1204 at
channel 6. The radio 1204 may be impacted by the strong TX power of
channel 6, causing non-linearity behavior (TX blocking), as
illustrated in the hashed region 1216 of graph 1206. For example,
the transmit signal may be 10 dBm per the channel bandwidth at
channel 6 at 2437 MHz at an antenna port of antenna 1210 of radio
1202 (e.g., -43 dBm/chBW at channel 6 at 2437 MHz). The TX signal
causes non-linearity on the LNA input of the receiver. To avoid or
reduce the non-linearity on the receiver caused by the ACI, the
first device's radio 902 should have ACI less than an equivalent
noise floor on the receiver. By adding a 30 dB isolation between
the radio 1202 and radio 1204, the de-sense on the receiver can be
further reduced or avoided. This permits the first device and the
second device to communicate on two channels (e.g., channel 1 and
6) at the same time without de-sense on the receiver.
FIG. 13 illustrates a multi-radio, multi-channel (MRMC) network
device 1300 according to one embodiment. The MRMC network 1300
includes a metal housing 1302 that has eight sectors 1304-1318.
Each of the eight sectors 1304-1318 has a truncated pyramid
structure with a top portion and four side portions that define a
recessed region of the respective truncated pyramid structure. The
truncated pyramid structures are disposed on their sides in a
horizontal plane and arranged in a circular arraignment with two
adjacent sectors sharing at least one common side portion. The
truncated pyramid structure may form an octagonal prism for the
metal housing 1302. The top portion and the four side portions may
be metal surfaces or have portions of metal. Also, the outer top
surfaces of the eight sectors form an inner chamber 1311 in a
center of the metal housing 1302. In particular, the sector 1308
may be considered a reflective chamber that includes an top portion
1330, a first side portion 1332, a second side portion 1334, a
third side portion 1336, and a fourth side portion 1338. The other
sectors 1304, 1306, 1310, 1312, 1314, 1316, and 1318 may have
similar metal portions or surfaces as reflective chambers as the
sector 1308. Similarly, the inner chamber 1311 can be considered
reflective. For example, a circuit board may include a metal ground
plane that is a reflective surface for the top antenna, as well as
for the bottom antenna. The opposite sides of the metal surfaces of
the reflective chambers also are reflective for the top and bottom
antennas.
In the depicted embodiment, the MRMC network 1300 includes a
circuit board 1320 disposed within the metal housing 1302. In
particular, the circuit board 1320 may include multiple portions,
such as a first portion disposed in the inner chamber 1311. There
may be a second portion of the circuit board 1320 disposed within a
first sector 1304 and a third portion of the circuit board 1320
disposed within a second sector 1306. These portions may extend to
an outer side of the metal housing 1302. The circuit board 1320 may
also include smaller portions that are disposed in the other
sectors 1308-1318 to accommodate some of the antenna pairs disposed
within the respective sectors.
In the depicted embodiment, the MRMC network 1300 includes eight
pairs of antennas 1340, each pair being disposed in one of the
eight sectors 1304-1318. Each pair includes a horizontal
orientation antenna and a vertical orientation antenna. The eight
pairs of antennas 1340 may be disposed on, above, or below
corresponding sections of the circuit board 1320. In one
embodiment, each of the eight pairs of antennas 1340 is a pair of
cross polarized dipole antennas, a pair of vertical polarized
dipole antennas, or a pair of cross polarized patch antennas.
In some embodiments, the MRMC network 1300 includes a top antenna
disposed on a top side of the circuit board 1320 within the inner
chamber 1311 and a bottom antenna disposed on a bottom side of the
circuit board 1320 within the inner chamber 1311. In the depicted
embodiment, top antennas 1342, 1344 are disposed above the circuit
board 1320, and bottom antennas 1346, 1348 are disposed below the
circuit board 1320. The top antennas 1342, 1344 and the bottom
antennas 1346, 1348 are helix coil antennas. In other embodiments,
the top and bottom antennas may be other types of antennas, such as
patch antennas, monopoles, dipoles, loops, folded monopoles, or the
like.
In the depicted embodiment, the eight pairs of antennas 1340, the
top antennas 1342, 1344, and the bottom antennas 1346, 1348 are
design to radiate electromagnetic energy in a first frequency
range, such as the 5 GHz band of the Wi-Fi.RTM. technologies. The
metal of the top portion and the four side portions of each of the
eight sectors operate as a reflector chamber. For example, the
metal of the top portion 1330 and the four side portions 1332-1338
of the sector 1308 operate as a reflector chamber for the pair of
antennas 1340 within the respective chamber. The reflective chamber
reflects the electromagnetic energy, radiated by the horizontal
orientation antenna, in a first directional radiation pattern with
high gain in a direction along a center axis of the sector 1308
(e.g., a truncated pyramid structure) and reflects the
electromagnetic energy, radiated by the vertical orientation
antenna, in a second directional radiation pattern with high gain
in the direction along the center axis of the sector 1308. The gain
the first direction is considered higher than the gain in other
directions, such as an opposite direction than the first direction.
The number of metal surfaces may impact the gain in the first
direction. As few as one metal surface can be used to reflect the
electromagnetic energy. However, if more than three metal surfaces,
the gain in the first direction can be increased.
In the depicted embodiment, the MRMC network 1300 includes a first
omni-directional antenna 1350 (e.g., dual-band WLAN antenna)
disposed on the top side of the second portion of the circuit board
1320 disposed within the sector 1304 (i.e., a first of the eight
sectors). In a further embodiment, a second omni-directional
antenna 1352 is disposed on the top side of the third portion of
the circuit board 1320 disposed within the sector 1306 (i.e., a
second of the eight sectors). The first omni-directional antenna
1350 and the second omni-directional antenna 1352 are designed to
radiate electromagnetic energy in the first frequency range (e.g.,
5 GHz band) and a second frequency range (e.g., 2.4 GHz band).
In the depicted embodiment, the MRMC network 1300 includes a first
cellular antenna 1354 (e.g., WWAN antenna) disposed on the top side
of the second portion of the circuit board 1320 disposed within the
sector 1304 (i.e., a first of the eight sectors). In a further
embodiment, a second cellular antenna 1356 is disposed on the top
side of the third portion of the circuit board 1320 disposed within
the sector 1306 (i.e., a second of the eight sectors). The first
cellular antenna 1354 and the second cellular antenna 1356 are
designed to radiate electromagnetic energy in a third frequency
range. For examples, the third frequency range may be the 900 MHz
band for the 2G specification, the 1800 MHz band for the 2G
specification, the B1 band for the 3G specification, the B8 band
for the 3G specification, or the B40 band for the LTE
specification.
In the depicted embodiment, the MRMC network 1300 includes a first
RF radio (not illustrated in FIG. 13) disposed on the circuit board
1320 and coupled to the first cellular antenna 1354 and the second
cellular antenna 1356. The first RF radio causes the first cellular
antenna 1354, the second cellular antenna 1356, or both to radiate
the electromagnetic energy in the third frequency range. In a
further embodiment, multiple RF radios (not illustrated in FIG. 13)
are disposed on the circuit board 1320 and coupled to the eight
pairs of antennas 1340, the top antennas 1342, 1344, and the bottom
antennas 1346, 1348. The RF radios cause different combinations of
one or more of the eight pairs of antennas 1340, the top antennas
1342, 1344, and the bottom antennas 1346, 1348 to radiate the
electromagnetic energy in the first frequency range (e.g., 2.4 GHz
band). In a further embodiment, a second RF radio (not illustrated
in FIG. 13) is disposed on the circuit board 1320 and coupled to
the first omni-directional antenna 1350 and the second
omni-directional antenna 1352. The second RF radio cause the first
omni-directional antenna 1350, the second omni-directional antenna
1352, or both to radiate the electromagnetic energy in the first
frequency range (e.g., 5 GHz band).
In the depicted embodiment, the MRMC network 1300 includes a third
RF radio (not illustrated in FIG. 13) disposed on the circuit board
1320 and coupled to the first omni-directional antenna 1350 and the
second omni-directional antenna 1352. The second RF radio cause the
first omni-directional antenna 1350, the second omni-directional
antenna 1352, or both to radiate the electromagnetic energy in the
second frequency range (e.g., 2.4 GHz band).
FIG. 14 is a block diagram of a network hardware device 1400
according to one embodiment. The network hardware device 1400 may
correspond to the network hardware device 102-110 of FIG. 1. In
another embodiment, the network hardware device 1400 may correspond
to the network hardware devices 202-210 in FIG. 2. In another
embodiment, the network hardware device 1400 may correspond to the
mesh node 300 of FIG. 3. Alternatively, the network hardware device
1400 may be other electronic devices, as described herein.
The network hardware device 1400 includes one or more processor(s)
1430, such as one or more CPUs, microcontrollers, field
programmable gate arrays, or other types of processors. The network
hardware device 1400 also includes system memory 1406, which may
correspond to any combination of volatile and/or non-volatile
storage mechanisms. The system memory 1406 stores information that
provides operating system component 1408, various program modules
1410, program data 1412, and/or other components. In one
embodiment, the system memory 1406 stores instructions of methods
to control operation of the network hardware device 1400. The
network hardware device 1400 performs functions by using the
processor(s) 1430 to execute instructions provided by the system
memory 1406.
The network hardware device 1400 also includes a data storage
device 1414 that may be composed of one or more types of removable
storage and/or one or more types of non-removable storage. The data
storage device 1414 includes a computer-readable storage medium
1416 on which is stored one or more sets of instructions embodying
any of the methodologies or functions described herein.
Instructions for the program modules 1410 may reside, completely or
at least partially, within the computer-readable storage medium
1416, system memory 1406 and/or within the processor(s) 1430 during
execution thereof by the network hardware device 1400, the system
memory 1406 and the processor(s) 1430 also constituting
computer-readable media. The network hardware device 1400 may also
include one or more input devices 1418 (keyboard, mouse device,
specialized selection keys, etc.) and one or more output devices
1420 (displays, printers, audio output mechanisms, etc.).
The network hardware device 1400 further includes a modem 1422 to
allow the network hardware device 1400 to communicate via a
wireless connections (e.g., such as provided by the wireless
communication system) with other computing devices, such as remote
computers, an item providing system, and so forth. The modem 1422
can be connected to one or more RF modules 1486. The RF modules
1486 may be a WLAN module, a WAN module, PAN module, GPS module, or
the like. The antenna structures (antenna(s) 1484, 1485, 1487) are
coupled to the RF circuitry 1483, which is coupled to the modem
1422. The RF circuitry 1483 may include radio front-end circuitry,
antenna switching circuitry, impedance matching circuitry, or the
like. In one embodiment, the RF circuitry 1483 includes the RFFE
circuitry with high selectivity performance as described in the
various embodiments of FIGS. 5-12. The antennas 1484 may be GPS
antennas, NFC antennas, other WAN antennas, WLAN or PAN antennas,
or the like. The modem 1422 allows the network hardware device 1400
to handle both voice and non-voice communications (such as
communications for text messages, multimedia messages, media
downloads, web browsing, etc.) with a wireless communication
system. The modem 1422 may provide network connectivity using any
type of mobile network technology including, for example, cellular
digital packet data (CDPD), general packet radio service (GPRS),
EDGE, universal mobile telecommunications system (UMTS), 1 times
radio transmission technology (1.times.RTT), evaluation data
optimized (EVDO), high-speed down-link packet access (HSDPA),
Wi-Fi.RTM., Long Term Evolution (LTE) and LTE Advanced (sometimes
generally referred to as 4G), etc.
The modem 1422 may generate signals and send these signals to
antenna(s) 1484 of a first type (e.g., WLAN 5 GHz), antenna(s) 1485
of a second type (e.g., WLAN 2.4 GHz), and/or antenna(s) 1487 of a
third type (e.g., WAN), via RF circuitry 1483, and RF module(s)
1486 as descried herein. Antennas 1484, 1485, 1487 may be
configured to transmit in different frequency bands and/or using
different wireless communication protocols. The antennas 1484,
1485, 1487 may be directional, omnidirectional, or non-directional
antennas. In addition to sending data, antennas 1484, 1485, 1487
may also receive data, which is sent to appropriate RF modules
connected to the antennas. One of the antennas 1484, 1485, 1487 may
be any combination of the antenna structures described herein.
In one embodiment, the network hardware device 1400 establishes a
first connection using a first wireless communication protocol, and
a second connection using a different wireless communication
protocol. The first wireless connection and second wireless
connection may be active concurrently, for example, if a network
hardware device is receiving a media item from another network
hardware device (e.g., a mini-POP node) via the first connection)
and transferring a file to another user device (e.g., via the
second connection) at the same time. Alternatively, the two
connections may be active concurrently during wireless
communications with multiple devices. In one embodiment, the first
wireless connection is associated with a first resonant mode of an
antenna structure that operates at a first frequency band and the
second wireless connection is associated with a second resonant
mode of the antenna structure that operates at a second frequency
band. In another embodiment, the first wireless connection is
associated with a first antenna structure and the second wireless
connection is associated with a second antenna. In other
embodiments, the first wireless connection may be associated with
content distribution within mesh nodes of the WMN and the second
wireless connection may be associated with serving a content file
to a client consumption device, as described herein.
Though a modem 1422 is shown to control transmission and reception
via antenna (1484, 1485, 1487), the network hardware device 1400
may alternatively include multiple modems, each of which is
configured to transmit/receive data via a different antenna and/or
wireless transmission protocol.
In the above description, numerous details are set forth. It will
be apparent, however, to one of ordinary skill in the art having
the benefit of this disclosure, that embodiments may be practiced
without these specific details. In some instances, well-known
structures and devices are shown in block diagram form, rather than
in detail, in order to avoid obscuring the description.
Some portions of the detailed description are presented in terms of
algorithms and symbolic representations of operations on data bits
within a computer memory. These algorithmic descriptions and
representations are the means used by those skilled in the data
processing arts to most effectively convey the substance of their
work to others skilled in the art. An algorithm is here, and
generally, conceived to be a self-consistent sequence of steps
leading to a desired result. The steps are those requiring physical
manipulations of physical quantities. Usually, though not
necessarily, these quantities take the form of electrical or
magnetic signals capable of being stored, transferred, combined,
compared, and otherwise manipulated. It has proven convenient at
times, principally for reasons of common usage, to refer to these
signals as bits, values, elements, symbols, characters, terms,
numbers or the like.
It should be borne in mind, however, that all of these and similar
terms are to be associated with the appropriate physical quantities
and are merely convenient labels applied to these quantities.
Unless specifically stated otherwise as apparent from the above
discussion, it is appreciated that throughout the description,
discussions utilizing terms such as "inducing," "parasitically
inducing," "radiating," "detecting," determining," "generating,"
"communicating," "receiving," "disabling," or the like, refer to
the actions and processes of a computer system, or similar
electronic computing device, that manipulates and transforms data
represented as physical (e.g., electronic) quantities within the
computer system's registers and memories into other data similarly
represented as physical quantities within the computer system
memories or registers or other such information storage,
transmission or display devices.
Embodiments also relate to an apparatus for performing the
operations herein. This apparatus may be specially constructed for
the required purposes, or it may comprise a general-purpose
computer selectively activated or reconfigured by a computer
program stored in the computer. Such a computer program may be
stored in a computer readable storage medium, such as, but not
limited to, any type of disk including floppy disks, optical disks,
CD-ROMs and magnetic-optical disks, read-only memories (ROMs),
random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical
cards, or any type of media suitable for storing electronic
instructions.
The algorithms and displays presented herein are not inherently
related to any particular computer or other apparatus. Various
general-purpose systems may be used with programs in accordance
with the teachings herein, or it may prove convenient to construct
a more specialized apparatus to perform the required method steps.
The required structure for a variety of these systems will appear
from the description below. In addition, the present embodiments
are not described with reference to any particular programming
language. It will be appreciated that a variety of programming
languages may be used to implement the teachings of the present
invention as described herein. It should also be noted that the
terms "when" or the phrase "in response to," as used herein, should
be understood to indicate that there may be intervening time,
intervening events, or both before the identified operation is
performed.
It is to be understood that the above description is intended to be
illustrative, and not restrictive. Many other embodiments will be
apparent to those of skill in the art upon reading and
understanding the above description. The scope of the present
embodiments should, therefore, be determined with reference to the
appended claims, along with the full scope of equivalents to which
such claims are entitled.
* * * * *